JP2015214521A - Purification method of compound, production method of polymeric compound, and photolithographic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purification method by which a content of metal impurities of a hydrophilic compound with low volatility can be reduced, a production method by which a polymeric compound with a reduced content of metal impurities can be produced, and a photolithographic material with a reduced content of metal impurities.SOLUTION: A purification method for a hydrophilic compound that is liquid or solid at 200°C under atmospheric pressure is provided, which includes the following step (I) and step (II). In step (I), a hydrophilic compound that is liquid or solid at 200°C under atmospheric pressure and contains at least one metal in Na, Ca, Fe and Zn is dissolved in a solvent having a hydroxyl group and a content of 50 mass ppb or less of each metal in Na, Ca, Fe and Zn; and the obtained solution is brought into contact with an anion exchange resin and a cation exchange resin. In step (II), after step (I), crystallization is carried out to recover the hydrophilic compound.

Description

  The present invention relates to a method for purifying a hydrophilic compound that is liquid or solid at 200 ° C. and atmospheric pressure, a method for producing a polymer compound, and a photolithography material.

  There are various materials for fine processing of semiconductors. For example, as a photolithography material for manufacturing a semiconductor, a photolithography solution obtained by adding an additive, an acid generator, a solvent and the like to a polymer obtained by polymerizing one to several kinds of monomers is used. In general, when a large amount of impurities is contained in the photolithography liquid, the photolithography performance is deteriorated, so that a photolithography liquid is manufactured using a purified polymer as a raw material (for example, Patent Document 1). However, even if a purified polymer is used as a raw material, there are many impurities in the photolithography liquid, and a decrease in photolithography performance cannot be sufficiently suppressed.

In the production process of a monomer that is a raw material of a polymer, an acid, an alkali, a metal or the like is often used (for example, Patent Document 2).
The fact that acids, alkalis, metals, etc. derived from the monomer production process are contained in the polymer as impurities, and these impurities cannot be sufficiently removed even if the polymer is purified, is considered to be one of the causes for the decline in photolithography performance. . In particular, even a slight amount of metal impurities in the polymer has a concern that not only the photolithography performance but also the performance and stability of the semiconductor device to be manufactured may be lowered.

When the monomer is a lipophilic compound, a method of dissolving the monomer in an organic solvent that can be easily separated from water and performing a liquid separation operation with water is generally used as a method for reducing metal impurities. In this method, since the monomer is dissolved in the oil phase and the metal impurities are dissolved in the aqueous phase, a compound with less metal impurities can be obtained by collecting the oil phase.
Further, when the monomer is a low-boiling compound, a method of distilling a compound with few metal impurities by distillation can be used.
However, when the monomer is a hydrophilic compound, the monomer and the metal impurities are both distributed to the aqueous phase during the liquid separation operation, so that it is difficult to reduce the metal content by the liquid separation operation. If the monomer is a hydrophilic compound that is difficult to volatilize or is a hydrophilic compound that is easily thermally decomposed, the distillation operation cannot be applied.

International Publication No. 2003/082933 JP-A-8-325245

  The present invention has been made in view of the above circumstances, a purification method that can reduce the metal impurity content of a hydrophilic compound that is difficult to volatilize, a production method that can produce a polymer compound with a low metal impurity content, and a metal impurity content An object is to provide a small amount of photolithography material.

The present invention has the following aspects.
[1] A method for purifying a hydrophilic compound that is liquid or solid under the conditions of 200 ° C. and atmospheric pressure, comprising the following steps (I) and (II).
Step (I): A hydrophilic compound containing at least one metal selected from Na, Ca, Fe and Zn, which is liquid or solid under the conditions of 200 ° C. and atmospheric pressure, Na, Ca, Fe and The process of making it melt | dissolve in the solvent which has a hydroxyl group whose content of each metal of Zn is 50 mass ppb or less, and contacting the obtained solution, an anion exchange resin, and a cation exchange resin.
Step (II): A step of performing crystallization after the step (I) to recover the hydrophilic compound.
[2] The purification method according to [1], wherein the hydrophilic compound is a compound represented by the following general formula (B).

（式（Ｂ）中、Ｒ^１、Ｒ^２はそれぞれ独立して、２価の炭化水素基、又は酸素原子を含む２価の基を表し、Ｒ^３は、１価の炭化水素基、又は酸素原子を含む１価の基を表す。）

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.)

[3] The purification method according to [1] or [2], wherein the content of each metal of Na, Ca, Fe and Zn in the solvent having a hydroxyl group is 30 mass ppb or less in the step (I). .
[4] In the step (II), the crystallization is performed using a solvent having a hydroxyl group in which the content of each metal of Na, Ca, Fe and Zn is 50 ppb or less. [1] to [3] The purification method according to any one of the above.
[5] A method for producing a polymer compound, comprising the following step (α) and step (β).
(Α) A compound represented by the following general formula (B) in which the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less through at least the following step (i) and step (ii) Obtaining.
(I) A compound represented by the following general formula (B) containing at least one metal selected from Na, Ca, Fe and Zn has a content of each metal of Na, Ca, Fe and Zn of 50 mass. The process of making it melt | dissolve in the solvent which has a hydroxyl group which is below ppb, and contacting the obtained solution, an anion exchange resin, and a cation exchange resin.
(Ii) A step of performing crystallization after the step (i) to recover the compound represented by the general formula (B).
(Β) A monomer component containing the compound represented by the general formula (B) obtained in the step (α), wherein the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less. A step of obtaining a polymer compound by polycondensation reaction in the presence of an acid catalyst.

（式（Ｂ）中、Ｒ^１、Ｒ^２はそれぞれ独立して、２価の炭化水素基、又は酸素原子を含む２価の基を表し、Ｒ^３は、１価の炭化水素基、又は酸素原子を含む１価の基を表す。）

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.)

  [6] A photolithography material comprising a compound represented by the following general formula (B), wherein the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less.

（式（Ｂ）中、Ｒ^１、Ｒ^２はそれぞれ独立して、２価の炭化水素基、又は酸素原子を含む２価の基を表し、Ｒ^３は、１価の炭化水素基、又は酸素原子を含む１価の基を表す。）

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.)

  According to the present invention, there are provided a purification method capable of reducing the metal impurity content of a hydrophilic and high boiling point compound, a production method capable of producing a polymer compound having a low metal impurity content, and a photolithography material having a low metal impurity content. Can be provided.

(Purification method)
The purification method of the present invention includes the following step (I) and step (II).
Step (I): A hydrophilic compound containing at least one metal selected from Na, Ca, Fe and Zn and having a boiling point of 200 ° C. or higher, and the content of each metal of Na, Ca, Fe and Zn is 50 mass. The process of making it melt | dissolve in the solvent which has a hydroxyl group which is below ppb, and contacting the obtained solution with an anion exchange resin and a cation exchange resin.
Step (II): Step of recovering the hydrophilic compound having a boiling point of 200 ° C. or higher by crystallization after the step (I).

<Hydrophilic compound that is liquid or solid under conditions of 200 ° C. and atmospheric pressure>
“Hydrophilic” in a hydrophilic compound that is liquid or solid under the conditions of 200 ° C. and atmospheric pressure (hereinafter also referred to as low-volatility hydrophilic compound) refers to water at 25 ° C. and a mass ratio of 1: 1. This means that they are compatible with each other without being separated.
It is preferable that the low-volatile hydrophilic compound does not dissolve in a water-insoluble solvent (for example, a water-insoluble compound of the hazardous material class 4 of the Fire Service Act).
Since the low-volatile hydrophilic compound is difficult to purify by distillation, the usefulness of the purification method of the present invention is high.
Examples of the compound that is liquid or solid at 200 ° C. and atmospheric pressure include compounds having a boiling point of 200 ° C. or higher, compounds having no boiling point, and the like.
The low-volatile hydrophilic compound preferably has a melting point of 100 ° C. or higher, particularly preferably 150 ° C. or higher.

  As a low-volatile hydrophilic compound, the compound (henceforth a compound (B)) represented by the following general formula (B) is mentioned, for example.

（式（Ｂ）中、Ｒ^１、Ｒ^２はそれぞれ独立して、２価の炭化水素基、又は酸素原子を含む２価の基を表し、Ｒ^３は、１価の炭化水素基、又は酸素原子を含む１価の基を表す。）

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.)

Examples of the divalent hydrocarbon group for R ¹ and R ² include an alkylene group, and an alkylene group is preferable. The alkylene group is particularly preferably an ethylene group.
Examples of the divalent group containing an oxygen atom include a group containing an oxygen atom between carbon atoms of a hydrocarbon group (an ether group or a polyether group).
R ¹ and R ² are each independently preferably a divalent hydrocarbon group, more preferably an alkylene group, and particularly preferably an ethylene group.

Examples of the monovalent hydrocarbon group for R ³ include an alkyl group and an alkenyl group.
Examples of the monovalent group containing an oxygen atom include groups containing a hydroxyl group such as —R ⁴ —OH (R ⁴ represents a hydrocarbon group). Examples of the hydrocarbon group for R ⁴ are the same as those described above.
R ³ is preferably a group containing a hydroxyl group, more preferably —R ⁴ —OH, and particularly preferably —CH ₂ —CH ₂ —OH.

As the compound (B), those in which R ¹ and R ² in the formula (B) are each independently a hydrocarbon group and R ³ is a group containing a hydroxyl group are preferable, and R ¹ and R ² are each ethylene. Particularly preferred is a group wherein R ³ is —CH ₂ —CH ₂ —OH.

  The low-volatility hydrophilic compound used in the purification method of the present invention, that is, the (unpurified) low-volatility hydrophilic compound before the step (I) is at least one of Na, Ca, Fe and Zn Of metals.

As the low-volatile hydrophilic compound containing the metal, a commercially available compound can be used as long as the desired compound is commercially available. You may use what was manufactured by the well-known method.
For example, the metal-containing compound (B) is available as a commercial product, and can also be produced by the method described in JP-A-8-325245.
The compound (B) contains at least one metal of Na, Ca, Fe and Zn as impurities.

<Process (I)>
In step (I), first, a low-volatile hydrophilic compound containing at least one metal selected from Na, Ca, Fe and Zn is dissolved in a solvent having a hydroxyl group to obtain a solution.

A solvent having a hydroxyl group can dissolve a low-volatile hydrophilic compound.
Examples of the solvent having a hydroxyl group include alcohols such as water (ultra pure water), methanol, and ethanol. Any one of these solvents may be used alone, or two or more thereof may be mixed and used.

As the solvent having a hydroxyl group, a solvent having a metal content of Na, Ca, Fe and Zn of 50 mass ppb or less is used. The content of each metal of Na, Ca, Fe and Zn in the solvent having a hydroxyl group is preferably 30 mass ppb or less.
When the content of each metal in the solvent having a hydroxyl group is not more than the above upper limit, each metal in the low-volatile hydrophilic compound can be effectively reduced. Therefore, for example, when a low-volatile hydrophilic compound is a monomer used as a raw material for a polymer compound for photolithography, the polymer compound produced using the monomer has a low content of each of the above metals, and photolithography. Good photolithography performance can be achieved when used in the process.

  The content of the low volatile hydrophilic compound in the solution is not particularly limited. An amount that completely dissolves in a solvent having a hydroxyl group at a temperature of 6 to 100 ° C. (no solid content remains) is preferable in that crystals of a low-volatile hydrophilic compound are easily precipitated in the step (II).

Next, the obtained solution is brought into contact with an anion exchange resin and a cation exchange resin. By making it contact with both an anion exchange resin and a cation exchange resin, the reduction effect of each metal in a low-volatile hydrophilic compound will be excellent.
The anion exchange resin and the cation exchange resin will be described later in detail.

As a method of bringing the solution into contact with each ion exchange resin, (1) a method in which the solution is brought into contact with a mixed resin of an anion exchange resin and a cation exchange resin, and (2) a solution in contact with the anion exchange resin. And then contacting with the cation exchange resin, and (3) a method of bringing the solution into contact with the cation exchange resin and then contacting with the anion exchange resin.
From the viewpoint of workability and the like, the method (1) is preferable.

99-0.1 mass% is preferable with respect to the low-volatile hydrophilic compound (100 mass%) in a solution, and, as for the usage-amount of an anion exchange resin, 80-0.1 mass% is more preferable.
99-0.1 mass% is preferable with respect to the low-volatile hydrophilic compound (100 mass%) in a solution, and, as for the usage-amount of a cation exchange resin, 80-0.1 mass% is more preferable.
When the used amount of each of the anion exchange resin and the cation exchange resin is equal to or higher than the lower limit of the above range, the metal, Na, Ca, Fe and Zn are excellent in removal effect, and when the amount is lower than the upper limit, the yield Excellent in stability, manufacturing cost, etc.

  The mass ratio of the anion exchange resin to the cation exchange resin is preferably, for example, anion exchange resin / cation exchange resin = 1/99 to 99/1, and preferably 20/80 to 99/1. Is more preferable, and 60/40 to 99/1 is particularly preferable. When the mass ratio of the anion exchange resin / cation exchange resin is within the above range, the effect of reducing each metal of Na, Ca, Fe and Zn in the low-volatile hydrophilic compound is excellent.

  Each of the anion exchange resin and the cation exchange resin is previously washed with a solvent having a hydroxyl group in which the content of each metal of Na, Ca, Fe and Zn is 50 mass ppb or less before contacting with the solution. It is preferable to keep it. Examples of the solvent having a hydroxyl group include those described above.

Although the temperature at the time of making the said solution and each ion-exchange resin contact is not specifically limited, From viewpoints, such as refinement | purification efficiency improvement, 30 degreeC or more is preferable and 50 degreeC or more is more preferable.
Although the time which makes the said solution and each ion exchange resin contact is not specifically limited, From viewpoints, such as refinement | purification efficiency improvement, 20 minutes or more are preferable and 40 hours or more are more preferable.
In the case of the method (1), the above time is the time for contacting with the mixed resin, and in the case of the method (2) or (3), the time for contacting with the anion exchange resin and the cation exchange. It is the total of the time for contact with the resin.

The contact between the solution and each ion exchange resin is such that the content of each metal of Na, Ca, Fe and Zn in the low-volatile hydrophilic compound recovered in the next step (II) is 100 ppb or less. It is preferable to carry out. As for each metal of Na, Ca, Fe, and Zn in the low-volatile hydrophilic compound collect | recovered at process (II), 50 mass ppb or less is more preferable.
A low-volatile hydrophilic compound in which the content of each of Na, Ca, Fe, and Zn is not more than the above upper limit value is useful as a photolithography material or the like.
The content of each metal in the low-volatility hydrophilic compound recovered in step (II) can be adjusted by the amount of each ion exchange resin to be brought into contact with the solution, the temperature and time at the time of contact, and the like.

  After bringing the solution into contact with each ion exchange resin, if necessary, separating the solution in which the low-volatile hydrophilic compound is dissolved from each ion exchange resin by using a method such as filtration. it can.

Anion exchange resin:
Examples of the anion exchange resin include strong basic anion exchange resins (type I and type II) and weak base anion exchange resins.

The total exchange capacity of the strongly basic anion exchange resin is preferably 0.8 mg equivalent or more, more preferably 1.0 mg equivalent or more with respect to 1 mL of the swelling resin.
The water content of the strongly basic anion exchange resin is preferably 75% or less, and more preferably 70% or less.
The apparent density of the strongly basic anion exchange resin is preferably 650 to 750 g / L.

The total exchange capacity of the weakly basic anion exchange resin is preferably 1.2 mg equivalent or more, more preferably 1.5 mg equivalent or more with respect to 1 mL of the swelling resin. Moreover, it is preferable that it is 4.6 mg equivalent or more with respect to 1 g of dry resins.
The water content of the weakly basic anion exchange resin is preferably 70% or less, and more preferably 60% or less.
The apparent density of the weakly basic anion exchange resin is preferably 300 to 700 g / L.

A commercial item can be used as an anion exchange resin.
Examples of commercially available strong base anion exchange resins include “Amberlite IRA400”, “Allite DS-2”, “Allite DS-5” manufactured by Organo Corporation; “Dawex” manufactured by Wako Pure Chemical Industries, Ltd. “SBR-PC (OH)”, “Dawex MSA-2”; “Diaion PA Series”, “Diaion HPA25”, “Diaion SA Series” manufactured by Mitsubishi Chemical Corporation, and the like.
Examples of commercially available weakly basic anion exchange resins include “Amberlyst B20-HG · Dry”, “Amberlite IRA96”, “Orlite DS-6” manufactured by Organo Corporation; Wako Pure Chemical Industries, Ltd. “Diaion WA10”, “Diaion WA20 series”, “Diaion WA30” manufactured by Mitsubishi Chemical Corporation, and the like.

Cation exchange resin:
Examples of the cation exchange resin include strong acid cation exchange resins and weak acid cation exchange resins.

The total exchange capacity of the strongly acidic cation exchange resin is preferably 1.2 mg equivalent or more, more preferably 1.5 mg equivalent or more with respect to 1 mL of the swelling resin. Moreover, it is preferable that it is 4.7 mg equivalent or more with respect to 1 g of dry resin.
The water content of the strongly acidic cation exchange resin is preferably 70% or less, and more preferably 60% or less.
The apparent density of the strongly acidic cation exchange resin is preferably 550 to 900 g / L.

The total exchange capacity of the weakly acidic cation exchange resin is preferably 2.0 mg equivalent or more, more preferably 2.5 mg equivalent or more with respect to 1 mL of the swelling resin.
The moisture content of the weakly acidic cation exchange resin is preferably 70% or less, and more preferably 60% or less.
The apparent density of the weakly acidic cation exchange resin is preferably 600 to 700 g / L.

A commercial item can be used as a cation exchange resin.
Examples of commercially available strong acid cation exchange resins include “Amberlyst 15JS-HG · Dry”, “Amberlite IR120B”, “Allite DS-1”, “Allite DS-4” manufactured by Organo Corporation; “Daewex HCR-S” and “Dawex HCR-W2 (H)” manufactured by Yakuhin Co., Ltd .; “Diaion SK series”, “Diaion UBK series” and “Diaion PK series” manufactured by Mitsubishi Chemical Corporation Etc.
Examples of commercially available weak acid cation exchange resins include “Amberlite IRC76” manufactured by Organo Corporation, “Diaion WK Series”, “Diaion WK40L” manufactured by Mitsubishi Chemical Corporation, and the like.

<Process (II)>
After step (I), crystallization is performed to recover a low-volatile hydrophilic compound.
Any crystallization method may be used as long as it is a method of precipitating crystals from a liquid phase and thereby separating or concentrating specific components as crystals, and known crystallization methods can be used.

Crystallization is preferably performed using a solvent having a hydroxyl group in which the content of each metal of Na, Ca, Fe, and Zn is 50 mass ppb or less because of excellent metal impurity reduction effect.
Examples of the solvent having a hydroxyl group include alcohols such as water (ultra pure water), methanol, and ethanol. Any one of these solvents may be used alone, or two or more thereof may be mixed and used.
As for content of each metal of Na, Ca, Fe, and Zn in the solvent which has a hydroxyl group, it is more preferable that it is 30 mass ppb or less.

The method for performing crystallization using a solvent having a hydroxyl group in which the content of each metal of Na, Ca, Fe and Zn is 50 mass ppb or less is not particularly limited, and for example, the following (II-1) or ( II-2).
(II-1) A method of crystallizing a low-volatile hydrophilic compound by cooling the solution brought into contact with the anion exchange resin and the cation exchange resin in the step (I).
(II-2) A method for newly crystallizing a low-volatile hydrophilic compound using a solvent having a hydroxyl group in which the content of each metal of Na, Ca, Fe and Zn is 50 mass ppb or less.
From the viewpoint of productivity, the method (II-1) is preferred.

In the method (II-1), the solution is preferably cooled at a cooling rate of 5 to 15 ° C./hour.
The method (II-2) can be performed, for example, by the following procedure.
The solvent of the solution brought into contact with the anion exchange resin and the cation exchange resin in the step (I) is replaced with a solvent having a hydroxyl group in which the content of each metal of Na, Ca, Fe and Zn is 50 mass ppb or less. Then, the low-volatile hydrophilic compound is crystallized by cooling the obtained solution.
Preferred conditions for cooling the solution are the same as in the method (II-1).
The newly used solvent having a hydroxyl group may be the same as or different from that used in step (I). For example, a low-volatile hydrophilic compound having a lower solubility can be used.

By crystallization, a suspension containing low-volatility hydrophilic crystals is obtained.
Crystals of a low-volatile hydrophilic compound are recovered from the obtained suspension. The recovery of the low-volatile hydrophilic compound crystal can be performed by a known solid-liquid separation operation such as filtration.
After recovering the crystals of the low-volatile hydrophilic compound, drying or the like may be performed as necessary.

<Effect>
According to the purification method of the present invention, the compound to be purified is dissolved in a solvent having a hydroxyl group such as water, and the resulting solution is contacted with an anion exchange resin and a cation exchange resin, followed by crystallization. By simple operation, the content of each metal of Na, Ca, Fe, and Zn in the hydrophilic compound that dissolves in the solvent having a hydroxyl group can be reduced.
The purification method of the present invention can also be applied to cases where the hydrophilic compound has low volatility or is easily thermally decomposable (for example, decomposes at a temperature of 200 ° C. or lower).

Therefore, according to the purification method of the present invention, it is possible to provide a compound having a low metal impurity content that is suitable for use in a photolithography process or the like.
For example, the compound (B) is used as a monomer in the production of a polymer compound for photolithography, but often contains at least one metal of Na, Ca, Fe, and Zn as an impurity. Since the compound (B) is hydrophilic and has low volatility, it is difficult to reduce the content of each metal to, for example, 100 mass ppb or less by a conventional general method for purifying monomers. Therefore, the polymer compound obtained by using this contains at least one metal of Na, Ca, Fe, and Zn as impurities, and reduces the content of each metal by refining the polymer compound. It is also difficult. When the polymer compound is used for photolithography, the photolithography performance and the like are lowered by each metal of Na, Ca, Fe, and Zn.
According to the purification method of the present invention, the content of each metal of Na, Ca, Fe, and Zn in the compound (B) can be reduced to 100 mass ppb or less. The compound (B) in which the content of each metal of Na, Ca, Fe, and Zn is 100 mass ppb or less is useful as a photolithography material. As for content of each metal of Na, Ca, Fe, and Zn in a compound (B), 50 mass ppb or less is more preferable.

(Method for producing polymer compound)
The method for producing a polymer compound of the present invention includes the following step (α) and step (β).
(Α) A step of obtaining a compound (B) in which the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less through at least the following step (i) and step (ii).
(I) The compound (B) containing at least one metal of Na, Ca, Fe and Zn has a hydroxyl group whose content of each metal of Na, Ca, Fe and Zn is 50 mass ppb or less. The process which melt | dissolves in a solvent and contacts the obtained solution, an anion exchange resin, and a cation exchange resin.
(Ii) A step of recovering the compound (B) by crystallization after the step (i).
(Β) The monomer component containing the compound (B) obtained in the step (α) and containing Na, Ca, Fe, and Zn, each having a metal content of 100 mass ppb or less, is reacted in the presence of an acid catalyst. A step of obtaining a polymer compound by a condensation reaction.

<Process (α)>
Compound (B) is the same as that described in the description of the purification method of the present invention.
In step (α), step (i) and step (ii) can be carried out in the same manner as step (I) and step (II), respectively.
The step (α) may include other steps other than the step (i) and the step (ii) as necessary.

<Process (β)>
The acid catalyst used in the step (β) is not particularly limited. For example, carboxylic acid such as oxalic acid, maleic anhydride, maleic acid and the anhydride, sulfonic acid such as p-toluenesulfonic acid, methanesulfonic acid, naphthalenesulfonic acid and the anhydride, sulfuric acid, hydrochloric acid, nitric acid, etc. . Among these, sulfonic acid and its anhydride are preferable, and sulfonic acid is more preferable. Since sulfonic acid and its anhydride are strongly acidic, have high reactivity, and have a low water content that inhibits condensation polymerization, they are suitable as acid catalysts.
These acid catalysts may be used alone or in combination of two or more.

The monomer component to be subjected to the polycondensation reaction includes at least the compound (B) obtained in the step (α), wherein the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less. , May further contain other monomers.
Any other monomer may be used as long as it can undergo a polycondensation reaction with the compound (B), and a known monomer can be used depending on the polymer compound to be produced.

The polymer compound is not particularly limited as long as it is obtained by a polycondensation reaction in the presence of an acid catalyst, and examples thereof include a polyester polymer compound and a polyether polymer compound.
Among these, polyester polymer compounds are preferable in that they are excellent in etching rate and the like and are optimal for application to semiconductor lithography technology.

The polycondensation reaction can be performed by a known polymerization method such as a solution polymerization method, an emulsion polymerization method, a suspension polymerization method, or a bulk polymerization method.
When using a polymer compound as a polymer compound for lithography, a solution polymerization method is preferably used.

  Hereinafter, the process (β) will be described by taking as an example the case of producing a polyester polymer compound by a solution polymerization method.

As a monomer, a monomer having two or more carboxy groups (such as a dicarboxylic acid) and a monomer having two or more hydroxyl groups (such as a diol) are dissolved in a polymerization solvent and heated to an appropriate temperature for the polymerization reaction in the presence of an acid catalyst. The polycondensation reaction is performed, and after cooling to an appropriate temperature, a basic compound is added as a reaction terminator to terminate the polycondensation reaction. Thereby, a polyester polymer compound is obtained.
In this example, at least part of the monomer having two or more hydroxyl groups is a compound (B) in which the content of each metal of Na, Ca, Fe and Zn obtained in the step (α) is 100 mass ppb or less. ).

  In the polycondensation reaction, a monomer in which a functional group (carboxy group) of the monomer is protected with an alkyl group may be used instead of the monomer having two or more carboxy groups. This makes it possible to control dehydration and dealcoholization reactions and suppress gelation, etc., so that it is suitable for use as a polymer compound for photolithography, particularly as a polymer compound for an antireflection film. Can be obtained. As the alkyl group, a methyl group, an ethyl group and the like are preferable.

  Although it does not restrict | limit especially as a polymerization solvent used for manufacture of the said polyester polymer compound, The solvent which can melt | dissolve any of a monomer, an acid catalyst, and the polymer (polyester polymer compound) obtained is preferable. Examples of such an organic solvent include anisole, 1,4-dioxane, acetone, tetrahydrofuran (THF), methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), toluene, xylene and the like.

  The polycondensation reaction is preferably performed at 100 to 150 ° C., more preferably 120 to 145 ° C., from the viewpoint of shortening the reaction time until the target molecular weight is reached and precise control of the molecular weight.

  After the condensation polymerization reaction, a crosslinking agent may be added to the side chain of the produced polymer compound. By adding the cross-linking agent to the side chain, sublimation of the cross-linking agent that may cause foreign matters in the photolithography process can be prevented, and effects such as process contamination reduction can be achieved.

As the crosslinking agent, a compound having a site that absorbs actinic rays used in the photolithography process can be used. For example, glycoluril, methylated glycoluril, butylated glycoluril, tetramethoxyglycoluril, methylated melamine Examples thereof include a resin, N-methoxymethylmelamine, urethane urea, an amino group or a compound containing vinyl ether.
In particular, glycoluril and tetramethoxyglycoluril are preferable in that a polymer compound having excellent antireflection film performance can be obtained. In addition, since these have non-aromatic characteristics, the etching rate can be improved.

Examples of the method for adding a crosslinking agent to the side chain of the polymer compound include a method in which a crosslinking agent is added to the reaction solution (including the polymer compound) obtained by the condensation polymerization reaction and further reacted. As a result, a polymer compound in which a crosslinking agent is added to a functional group (hydroxyl group or the like) contained in the polymer compound and a crosslinking agent is added to the side chain is obtained.
From the viewpoint of both efficient progress of the crosslinking agent addition reaction and precise control of the molecular weight, the crosslinking agent addition reaction is preferably performed at 50 ° C. or less, more preferably 15 to 30 ° C., and still more preferably. 18-22 ° C.

  After the condensation polymerization reaction or after the cross-linking agent addition reaction, operations such as dilution, concentration, purification, reprecipitation, drying, and re-dissolution may be further performed as necessary.

<Effect>
According to the method for producing a polymer compound of the present invention, in step (α), compound (B) is dissolved in a solvent having a hydroxyl group such as water, and the resulting solution is treated with an anion exchange resin and a cation exchange. The content of each metal of Na, Ca, Fe, and Zn in the hydrophilic and low-volatile compound (B) can be reduced by a simple operation of crystallization after contacting with the resin. By using the compound (B) in which the content of each metal of Na, Ca, Fe, and Zn is reduced as a monomer, each metal of Na, Ca, Fe, and Zn is compared with the case where the process (α) is not performed. A polymer compound with a low content of can be obtained. For example, it is possible to obtain a polymer compound having a content of each metal of Na, Ca, Fe, and Zn of 50 mass ppb or less. As for content of each metal of Na, Ca, Fe, and Zn in a high molecular compound, 30 mass ppb or less is more preferable.

<Application>
The polymer compound obtained by the method for producing a polymer compound of the present invention is suitable as a polymer compound for photolithography used in the photolithography process.
Examples of the polymer compound for photolithography include a resist polymer compound used for forming a resist film, an antireflection film (TARC) formed on the upper layer of the resist film, or an antireflection film (BARC) formed on the lower layer of the resist film. ), A polymer compound for an antireflection film, a polymer compound for a gap fill film used for forming a gap fill film, a polymer compound for a top coat film used for forming a top coat film, and the like.

The mass average molecular weight (Mw) of the polymer compound for lithography is preferably from 1,000 to 200,000, more preferably from 2,000 to 40,000.
The Z-average molecular weight (Mz) of the polymer compound for lithography is preferably from 1,000 to 400,000, more preferably from 2,000 to 100,000.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
Unless otherwise specified, “%” and “ppb” in each example represent “mass%” and “mass ppb”, respectively.
The ultrapure water and high purity methanol used in each example are for semiconductors in which the content of each metal of Na, Ca, Fe and Zn is reduced to 30 ppb or less.
The measurement method used in each example is shown below.

<Metal impurity concentration measurement method>
The content (metal impurity concentration) of each metal of Na, Ca, Fe, and Zn in the compound (low volatile hydrophilic compound, polymer compound) was determined as follows.
A measurement sample was prepared by diluting 1.5 g of the dry powder of the compound 100 times with distilled and purified N-methyl-2-pyrrolidone.
The measurement sample was subjected to metal analysis of Na, Ca, Fe, and Zn with a high frequency inductively coupled plasma mass spectrometer (ICP-MS (Inductively Coupled Plasma Mass Spectrometer): 7500 cs manufactured by Agilent Technologies), and each metal in the measurement sample was analyzed. The ion concentration was measured. From the results, the metal impurity concentration in the compound (solid content) was determined.

<Measurement Method of Mass Average Molecular Weight (Mw) and Z Average Molecular Weight (Mz)>
The mass average molecular weight (Mw) and the Z average molecular weight (Mz) of the polymer compound were determined in terms of polystyrene by GPC (Gel Permeation Chromatography: “HLC8220GPC” manufactured by Tosoh Corporation). The measurement conditions are as follows.
Measurement sample: dry powder 50 mg / eluent 5 mL.
Eluent: 1.7 mM phosphoric acid / THF.
Separation column: “Shodex GPC K-805L” manufactured by Showa Denko KK
Measurement temperature: 40 ° C.
-Detector: A differential refractive index detector.

<Example 1>
Commercially available product of 1,3,5-tris (2-hydroxyethyl) isocyanurate (hereinafter abbreviated as THEIC) (product name: THEIC-G, Shikoku Kasei, no boiling point, flash point 227 ° C., melting point 133-138 ° C. ) (60.00 g, 0.231 mol) was added ultrapure water (36.00 g) and completely dissolved at 60 ° C. To the resulting solution, an anion exchange resin (ORGANO Amberlyst B20-HG · Dry) (1.2 g) and a cation exchange resin (ORGANO Amberlyst 15JS-HG · Dry) (1.2 g) previously washed with ultrapure water was added. ) And stirred at 60 ° C. for 1 hour. Thereafter, the cation exchange resin and the anion exchange resin were removed by filtration, and the filtrate was cooled to 5 ° C. at a rate of 20 ° C./hour for crystallization. Thereafter, filtration was performed, and the precipitated crystals were collected and dried under reduced pressure at 50 ° C. As a result, a purified product of THEIC (36.1 g, yield 60.2%) was obtained.

<Example 2>
Example 1 and Example 1 except that the amount of anion exchange resin (ORGANO Amberlyst B20-HG · Dry) and cation exchange resin (ORGANO Amberlyst 15JS-HG · Dry) was changed to 0.6 g, respectively. The same operation was performed to obtain a purified THEIC product (37.2 g, yield 62.0%).

<Example 3>
High-purity methanol (168.00 g) was added to a commercial product of THEIC (product name: THEIC-G, Shikoku Kasei) (60.00 g, 0.231 mol) and completely dissolved at 60 ° C. Anion exchange resin (ORGANO Amberlyst B20-HG · Dry) (1.2 g) and cation exchange resin (ORGANO Amberlyst 15JS-HG · Dry) (1.2 g) previously washed with high-purity methanol was added to the resulting solution. ) And stirred at 60 ° C. for 1 hour. Thereafter, the cation and anion mixed exchange resin was removed by filtration, and the filtrate was cooled to 5 ° C. at a rate of 20 ° C./hour for crystallization. Thereafter, filtration was performed, and the precipitated crystals were collected and dried under reduced pressure at 50 ° C. As a result, a refined THEIC product (39.1 g, yield 65.0%) was obtained.

<Example 4>
Example 3 and Example 3 except that the amounts of anion exchange resin (ORGANO Amberlyst B20-HG · Dry) and cation exchange resin (ORGANO Amberlyst 15JS-HG · Dry) were changed to 0.6 g, respectively. The same operation was performed to obtain a purified THEIC product (41.2 g, yield 68.7%).

<Comparative Example 1>
High-purity methanol (168.00 g) was added to a commercial product of THEIC (product name: THEIC-G, Shikoku Kasei) (60.00 g, 0.231 mol) and completely dissolved at 60 ° C. Crystallization was performed by cooling the obtained solution to 5 ° C. at a rate of 20 ° C./hour. Thereafter, filtration was performed, and the precipitated crystals were collected and dried under reduced pressure at 50 ° C. As a result, a purified product of THEIC (45.1 g, yield 75.0%) was obtained.

<Comparative Example 2>
Ultrapure water (36.00 g) was added to a commercial product of THEIC (product name: THEIC-G, Shikoku Kasei) (60.00 g, 0.231 mol) and completely dissolved at 60 ° C. A cation exchange resin (ORGANO Amberlyst 15JS-HG · Dry) (0.6 g) previously washed with ultrapure water was added to the resulting solution, and the mixture was stirred at 60 ° C. for 1 hour. Thereafter, the cation exchange resin was removed by filtration, and the filtrate was cooled to 5 ° C. at a rate of 20 ° C./hour for crystallization. Thereafter, filtration was performed, and the precipitated crystals were collected and dried under reduced pressure at 50 ° C. As a result, a purified product of THEIC (38.8 g, yield 64.7%) was obtained.

<Comparative Example 3>
Ultrapure water (36.00 g) was added to a commercial product of THEIC (product name: THEIC-G, Shikoku Kasei) (60.00 g, 0.231 mol) and completely dissolved at 60 ° C. An anion exchange resin (ORGANO Amberlyst B20-HG · Dry) (0.6 g) previously washed with ultrapure water was added to the obtained solution, and the mixture was stirred at 60 ° C. for 1 hour. Thereafter, the anion mixed exchange resin was removed by filtration, and the filtrate was cooled to 5 ° C. at a rate of 20 ° C./hour for crystallization. Thereafter, filtration was performed, and the precipitated crystals were collected and dried under reduced pressure at 50 ° C. As a result, a purified product of THEIC (38.5 g, yield 64.2%) was obtained.

About the commercially available product of THEIC used in each example of Examples 1 to 4 and Comparative Examples 1 to 3 (raw material before purification) and the purified product of THEIC obtained in each example, each metal of Na, Ca, Fe, and Zn The content (metal impurity concentration) was measured. The results are shown in Table 1.
Table 1 also shows the amount of anion exchange resin and cation exchange resin used in each example (ratio to the THEIC raw material (%)) and the type of solvent used in each example.

<Example 5>
Refined THEIC product obtained in Example 1 (33.56 g, 0.129 mol), dimethyl 2,3-naphthalenedicarboxylate (31.50 g, 0.129 mol), p-toluenesulfonic acid hydrate (pTSA) (1.303 g, 6.85 mmol) and anisole (39.80 g) were charged into a three-necked flask and polymerized at 130 ° C. for 8 hours while performing dehydration and demethanol reaction using a Dean-Stark trap. Then, it cooled to 50 degreeC and the reaction was stopped by adding triethylamine (0.693g, 6.85mmol).
The obtained polymerization solution was diluted with tetrahydrofuran (THF) (49.7 g) to obtain a diluted solution. This diluted solution is added to a mixture (poor solvent) of hexane (290.0 g) and 2-propanol (IPA) (870.0 g) to reprecipitate, and a polyester system having a structural unit represented by the following formula (2) Polymer compound 1 (mass average molecular weight (Mw): 6300, Z average molecular weight (Mz): 12500, yield: about 50%) was obtained.

<Example 6>
The purified THEIC product obtained in Example 3 (33.56 g, 0.129 mol), diethyl 1,2-cyclohexanedicarboxylate (29.45 g, 0.129 mol), pTSA (1.303 g, 6.85 mmol), and Anisole (39.80 g) was charged into a three-necked flask and polymerized at 135 ° C. for 10 hours while performing dehydration and deethanol reaction using a Dean-Stark trap. Then, after diluting with THF (44.7 g), tetramethoxyglycoluril (TMGU) (12.81 g, 40.24 mmol) was added and reacted at 20 ° C. for 5.5 hours, and then triethylamine (0.693 g, 6.85 mmol) was added to stop the reaction.
The obtained polymerization solution was added to a mixture (poor solvent) of hexane (290.0 g) and IPA (870.0 g) and reprecipitated, and the structural unit represented by the following formula (4) and the following formula (5 ), A polyester polymer compound 3 having a side chain and a cross-linking agent added (mass average molecular weight (Mw): 7500, Z average molecular weight (Mz): 14200, yield: about 40% )

<Comparative Example 4>
In Example 5, a polyester polymer compound (mass) was prepared in the same manner as in Example 5 except that a commercially available THEIC (product name: THEIC-G, Shikoku Kasei) was used instead of the purified THEIC. Average molecular weight (Mw): 6400, Z average molecular weight (Mz): 12600, yield: about 50%) was obtained.

<Comparative Example 5>
In Example 6, a polyester polymer compound (mass) was prepared in the same manner as in Example 6 except that a commercially available product of THEIC (product name: THEIC-G, Shikoku Kasei) was used instead of the purified product of THEIC. Average molecular weight (Mw): 7600, Z average molecular weight (Mz): 14400, yield: about 40%) was obtained.

About the polyester type polymer compound used in each example of Examples 5-6 and Comparative Examples 4-5, content (metal impurity concentration) of each metal of Na, Ca, Fe, and Zn was measured. The results are shown in Table 2.
Table 2 also shows whether the THEIC used in each example was purified.

As shown in Tables 1 and 2, Examples 1 and 2 were used in which the THEIC was dissolved in a solvent having a hydroxyl group, and the resulting solution was subjected to a purification treatment in which the anion exchange resin and the cation exchange resin were brought into contact with each other for crystallization. In No. 4, the content of each metal of Na, Ca, Fe, and Zn could be greatly reduced compared with that before the purification treatment.
On the other hand, Comparative Example 1 in which the solution was crystallized as it was without contacting the anion exchange resin and the cation exchange resin, and Comparative Example 2 in which the solution was brought into contact with only one of the anion exchange resin and the cation exchange resin. In -3, the content of each metal of Na, Ca, Fe, and Zn was reduced as compared with that before the treatment, but the reduction effect was inferior to that of Examples 1 to 4, and Na, Ca, Fe, The total content of Zn could not be made 100 ppb or less.

As shown in Table 2, in Examples 5 to 6 using the THEIC refined product obtained in Example 3, a polymer compound having a content of each metal of Na, Ca, Fe and Zn of 50 ppb or less was obtained. .
On the other hand, in Comparative Examples 4 to 5 using a THEIC immature product, the total content of Na, Ca, Fe and Zn in the polymer compound could not be reduced to 50 ppb or less. When such a polymer compound is used for, for example, photolithography, there is a concern that the photolithography performance is not sufficiently exhibited.
In each of Examples 5-6 and Comparative Examples 4-5, reprecipitation was performed after polymerization, but the above differences were found in the contents of each metal of Na, Ca, Fe, and Zn.

  From the above results, it was confirmed that according to the purification method of the present invention, the concentration of metal impurities in a hydrophilic and low-volatile compound such as THEIC can be efficiently reduced. In addition, by using the compound purified by the purification method of the present invention, sufficient performance is achieved when the content of each metal of Na, Ca, Fe, and Zn in the polymer compound is used as a composition for photolithography. It can be judged that it can be level.

Claims (6)

A method for purifying a hydrophilic compound that is liquid or solid under the conditions of 200 ° C. and atmospheric pressure, comprising the following steps (I) and (II).
Step (I): A hydrophilic compound containing at least one metal selected from Na, Ca, Fe and Zn, which is liquid or solid under the conditions of 200 ° C. and atmospheric pressure, Na, Ca, Fe and The process of making it melt | dissolve in the solvent which has a hydroxyl group whose content of each metal of Zn is 50 mass ppb or less, and contacting the obtained solution, an anion exchange resin, and a cation exchange resin.
Step (II): A step of performing crystallization after the step (I) to recover the hydrophilic compound. The purification method according to claim 1, wherein the hydrophilic compound is a compound represented by the following general formula (B).

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.)   The said purification method of Claim 1 or 2 whose content of each metal of Na, Ca, Fe, and Zn in the solvent which has the said hydroxyl group in the said process (I) is 30 mass ppb or less.   The said crystallization is performed in the said process (II) using the solvent which has a hydroxyl group whose content of each metal of Na, Ca, Fe, and Zn is 50 ppb or less. The purification method according to 1. The manufacturing method of a high molecular compound including the following process ((alpha)) and process ((beta)).
(Α) A compound represented by the following general formula (B) in which the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less through at least the following step (i) and step (ii) Obtaining.
(I) A compound represented by the following general formula (B) containing at least one metal selected from Na, Ca, Fe and Zn has a content of each metal of Na, Ca, Fe and Zn of 50 mass. The process of making it melt | dissolve in the solvent which has a hydroxyl group which is below ppb, and contacting the obtained solution, an anion exchange resin, and a cation exchange resin.
(Ii) A step of performing crystallization after the step (i) to recover the compound represented by the general formula (B).
(Β) A monomer component containing the compound represented by the general formula (B) obtained in the step (α), wherein the content of each metal of Na, Ca, Fe and Zn is 100 mass ppb or less. A step of obtaining a polymer compound by polycondensation reaction in the presence of an acid catalyst.

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.) Photolithographic material which consists of a compound represented by the following general formula (B) whose content of each metal of Na, Ca, Fe, and Zn is 100 mass ppb or less.

(In formula (B), R ¹ and R ² each independently represents a divalent hydrocarbon group or a divalent group containing an oxygen atom, and R ³ represents a monovalent hydrocarbon group or oxygen. Represents a monovalent group containing an atom.)