TW202302499A - Method for refining hydrolyzable organic solvent, and method for producing resin for refining hydrolyzable organic solvent - Google Patents

Abstract

The invention provides a method for refining a hydrolyzable organic solvent that suppresses the production of acid while enabling a reduction in the metal impurity concentration within the hydrolyzable organic solvent. The method for refining a hydrolyzable organic solvent has a refining step of bringing the hydrolyzable organic solvent into contact with a cation exchange resin optionally mixed with a chelating resin, wherein the volume fraction of the cation exchange resin relative within the total volume of the cation exchange resin and the optional chelating resin is within a range from 10 to 100%.

Description

Method for refining hydrolyzable organic solvent and method for producing resin for refining hydrolyzable organic solvent

The present invention relates to a method for refining a hydrolyzable organic solvent and a method for producing a resin for refining a hydrolyzable organic solvent.

Semiconductors are manufactured through hundreds of complex steps. The line width of the semiconductor is determined by the photoresist step. The photoresist step includes: the step of coating the photoresist on the silicon wafer, the exposure step of irradiating short-wavelength light from the light source through the photomask, the step of developing the photomask, the step of etching the part without photoresist, and the step of stripping the photoresist . The photoresist coated on the wafer is a solution obtained by dissolving an acid generator, resin solution, and additives in an organic solvent. The organic solvent uses esters such as PGMEA (propylene glycol monomethyl ether acetate) and ethyl lactate. It is mainly composed of organic solvents, PGME (propylene glycol monomethyl ether), cyclohexanone, etc.

In recent years, the processing dimension of the line width of semiconductors has become smaller and smaller year by year. The miniaturization of the semiconductor line width promotes the miniaturization and high-performance technology of IT equipment. With the miniaturization of the line width of semiconductors, the light source used in the exposure step has begun to increase the use of short-wavelength ArF, EUV, and X-rays from g-rays and i-rays to reduce the amount of impurities in organic solvents around photoresist coating. Also set lower. Among the impurities contained in the organic solvent, especially in the case of a large amount of residual metal elements, the metal elements may adhere to the wafer and degrade the performance of the semiconductor. Therefore, metal elements must be listed as reduction items.

On the other hand, ester-based organic solvents such as PGMEA used in semiconductor manufacturing are known to be hydrolyzed by contact with moisture, acids, and alkalis to generate acids. Therefore, someone has proposed the method of using distillation and chelating resin in the refining of ester-based organic solvents as a method for removing metal impurities without generating acid.

The following method is described in patent document 1: use deionized water, inorganic acid solution, and use ammonium hydroxide solution to clean chelate resin arbitrarily, after it is cleaned with organic solvent again, mix photoresist composition, and carry out Heat and filter to reduce metal ions in the photoresist composition. However, according to this method, especially Fe cannot be sufficiently removed.

Patent Document 2 describes a method in which the flow rate (SV value) of the passing liquid is reduced to 10 h ^-1 or less, and the resin solution for forming a photoresist film is passed through the resin solution in which ion exchange groups and/or chelating groups have been fixed to the polyolefin system. Filter substrate made of non-woven fabric. However, in Patent Document 2, only the Na concentration is described as the impurity concentration. According to the research of the present inventors, it is clear that compared with the case of using a chelating resin, the removal properties of heavy metals such as Fe and Cr are not good.

The method of using the chelating resin that has utilized the mineral acid solution to reduce the metal impurity content to remove the metal impurities in the treated liquids such as PGMEA is described in the patent document 3. However, as a result of further studies by the inventors of the present invention, it has been found that heavy metals such as Fe and Cr may not be sufficiently removed depending on the liquid to be treated which is the object of purification. [Prior Art Literature] [Patent Document]

Patent Document 1: Japanese PCT Publication No. 2000-501201 Patent Document 2: Japanese Patent Laid-Open No. 2013-061426 Patent Document 3: Japanese Patent Laid-Open No. 2019-141800

[Problem to be Solved by the Invention]

Therefore, the object of the present invention is to provide a method for producing a resin for refining a hydrolyzable organic solvent, which can suppress the generation of acid and reduce the concentration of metal impurities in the hydrolyzable organic solvent; Refining method. [Means to solve the problem]

In view of the problems referred to above, the result of the inventor's detailed study of the present case found that by using the cation-exchange resin mixed with the chelating resin arbitrarily, the hydrolyzable organic solvent can be suppressed to produce acid, and the metal that cannot be fully removed only with the chelating resin can be reduced, and then Complete the present invention.

That is, the method for refining a hydrolyzable organic solvent of the present invention is characterized in that it has: a refining step in which a cation exchange resin mixed with a chelating resin is contacted with a hydrolyzable organic solvent for refining; with respect to the cation exchange resin and For any total amount of the chelating resin, the volume ratio of the cation exchange resin is 10-100%.

Also, the method for producing the resin used for refining the hydrolyzable organic solvent of the present invention is characterized in that it has the step of arbitrarily mixing the chelating resin in the cation exchange resin; The volume ratio of the cation exchange resin is 10-100%. [Effect of Invention]

According to the present invention, there is provided a method for producing a resin for refining a hydrolyzable organic solvent, which can suppress the generation of acid and reduce the concentration of metal impurities in a hydrolyzable organic solvent; and a method for refining a hydrolyzable organic solvent using the resin .

The manufacturing method of the resin used for refining hydrolyzable organic solvent of the present invention has the step of arbitrarily mixing chelating resin in cation exchange resin. In addition, in the case of using only a cation exchange resin without using a chelate resin, this step can also be said to be a step of preparing a cation exchange resin. Also, the purification method of the hydrolyzable organic solvent of the present invention has a purification step in which the cation exchange resin optionally mixed with the chelate resin is brought into contact with the hydrolyzable organic solvent for purification. Relative to the total amount of the cation exchange resin and any chelating resin, the volume ratio of the cation exchange resin is 10-100%.

(hydrolyzable organic solvent) The hydrolyzable organic solvent used as the liquid to be purified in the present invention is an ester-based organic solvent that generates acid by hydrolysis. In addition, the liquid to be purified in the present invention may be a mixed solvent obtained by mixing at least two or more organic solvents including an ester-based organic solvent. The liquid to be purified is not particularly limited, and examples thereof include: PGMEA (propylene glycol monomethyl ether acetate), ethylene glycol monoethyl ether acetate, ethyl-3-ethoxypropyl acetate, ethyl lactate, lactic acid Organic ester solvents such as butyl ester, butyl acetate, and isoamyl acetate, and mixed solvents of these organic ester solvents with PGME (propylene glycol monomethyl ether), cyclohexanone, and the like. Among them, PGMEA or a mixed solvent of PGMEA/PGME is preferable. The ratio of PGMEA in the mixed solvent of PGMEA/PGME is not particularly limited, and can be appropriately adjusted according to the purpose.

The water concentration of the hydrolyzable organic solvent (before refining) used in the present invention is preferably 20 to 10000 mg/L from the viewpoint of hydrolysis inhibition and stability of metal refining performance. The upper limit of the water concentration should be low, more preferably 5000 mg/L, and even more preferably 1000 mg/L. In addition, the water concentration can be measured by the Karl Fisher method using, for example, a Karl Fisher volumetric moisture meter (trade name: Aquacounter AQ-2200, manufactured by Hiranuma Sangyo Co., Ltd.).

(Cation Exchange Resin) The ion exchange resin is obtained, for example, by introducing a functional group into a copolymer having a three-dimensional network structure obtained by copolymerizing styrene and divinylbenzene (DVB) in the presence of a catalyst and a dispersant. Examples of the cation exchange resin used in the present invention include strongly acidic cation exchange resins having sulfonic acid groups (—SO ₃ H) and weakly acidic cation exchange resins having carboxylic acid groups (—COOH). Also, the cation exchange resin may be of a gel type in which the resin has a small pore diameter and is transparent, and a macroreticular type (MR type) or a macroporous type (also a macroporous type) in which the pore diameter is large and has large pores. Called porous (porous) type, high porous (high porous) type). In the present invention, it is preferable to use a strongly acidic cation exchange resin from the viewpoint of metal removal. Among them, an MR type strongly acidic cation exchange resin is preferable from the standpoint of the balance between acid generation suppression and metal removal performance. Also, from the viewpoint of more effectively suppressing acid generation, a highly cross-linked gel-type strongly acidic cation exchange resin is preferable. In addition, the so-called highly cross-linked gel-type strongly acidic cation exchange resin specifically refers to a gel-type strongly acidic cation-exchange resin with a cross-linking degree of 16% to 24%.

The volume ratio of the cation exchange resin is 10-100%, preferably 20-100%, relative to the total amount of the cation exchange resin and any chelating resin described below. Here, the ratio of 100% means that only the cation exchange resin is used. According to the purification method of the present invention, even when only a cation exchange resin is used, acid generation can be suppressed, and metal impurities in the liquid to be purified can be reduced. From the viewpoint of more effectively suppressing the generation of acid, it is preferable to use the cation exchange resin and the chelating resin in a mixed bed or double bed. In this case, relative to the total amount of the cation exchange resin and the chelating resin, the volume ratio of the cation exchange resin is preferably 10%-50%, more preferably 10%-33%.

The cation exchange resins used in the present invention include, for example: AMBERLITE (registered trademark) IRN99H (gel-type strongly acidic cation exchange resin, trade name, manufactured by DuPont), AMBERLITE (registered trademark) CR99 K/350, TAPTEC ( Registered trademark) HCRS Na (both are gel-type strongly acidic cation exchange resins, trade name, manufactured by DuPont), AMBERJET (registered trademark) 1060H (gel-type strongly acidic cation exchange resin, trade name, Olucanau Co., Ltd.), ORLITE (registered trademark) DS-1 (gel-type strongly acidic cation exchange resin, trade name, Olucano Co., Ltd.), ORLITE (registered trademark) DS-4 (MR type Strongly acidic cation exchange resin, trade name, manufactured by Olucano Co., Ltd.), etc., but not limited thereto. The ionic form of the cation exchange resin is preferably a hydrogen ion form (H form) from the viewpoint of metal removal. In addition, when using resins in other ion forms (for example, sodium ion form, potassium ion form, etc.), it is advisable to convert the resin into H form by conventional methods before use.

(chelating resin) In the present invention, a chelate resin can be arbitrarily mixed with the cation exchange resin. In the case of mixing the chelating resin, the cation exchange resin and the chelating resin may be a mixed bed or a multiple bed. In either case, the effects of the present invention can be obtained. Chelating resins are resins with functional groups (chelating groups) that can form chelates (complexes) with metal ions. The functional group is not particularly limited as long as it can form a chelate (complex) with a metal ion. The functional group includes, for example, an aminomethyl phosphoric acid group, an iminodiacetoxy group, a thiol group, and a polyamine group. From the viewpoint of selectivity to various metal species, etc., the chelate resin preferably has an aminomethylphosphonic acid group or an iminodiacetoxy group as a functional group.

The ionic form of chelating resin is preferably H form. Chelating resins include, for example: AMBERSEP (registered trademark) IRC747UPS (trade name, manufactured by DuPont, chelating group: aminomethylphosphoryl group), AMBERSEP (registered trademark) IRC748 (trade name, manufactured by DuPont, chelating group : iminodiacetoxy group), ORLITE (registered trademark) DS-21 (trade name, manufactured by Olucano Co., Ltd., chelating group: aminomethylphosphoryl group), ORLITE (registered trademark) DS-22 (trade name, manufactured by Olucano Co., Ltd., chelating group: iminodiacetoxy), DIAION (registered trademark) CR11 (trade name, manufactured by Mitsubishi Chemical Co., Ltd., chelating group: iminodiacetate) Acetate group), S930 (trade name, manufactured by Purolite Co., Ltd., chelating group: iminodiacetoxy group), S950 (trade name, manufactured by Purolite Co., Ltd., chelating group: aminophosphoryl group), etc., but Not limited to these. In addition, when the ionic form of the above-mentioned resin is sodium ion form (Na form), it can be used after converting the ionic form from Na form to H form by a known method.

The chelating resin used among the present invention is a hydrogen ion form, and the total metal impurity amount dissolved when making the hydrochloric acid of concentration 3 mass % pass through this chelating resin with volume ratio 25 times amount should be below 5 μ g/mL-R. This commercially available product can also be used as a chelating resin. Here, "the volume ratio of 25 times" means passing hydrochloric acid having a volume 25 times the volume of the chelating resin. The unit "/mL-R" refers to "volume of chelating resin in saturated equilibrium per 1 mL". In addition, the so-called saturated equilibrium state refers to the state in which the chelate resin is brought into a saturated state by contacting the atmosphere at 25° C. with a relative humidity of 100% for more than 30 minutes. The so-called "passing hydrochloric acid" includes not only passing hydrochloric acid through the chelate resin, but also immersing the chelate resin in hydrochloric acid and the like. The total amount of metal impurities per 1 mL of the volume of the chelating resin (μg/mL-R), can be obtained from the amount of dissolved total metal impurities (μg/L), the volume of eluent used for dissolution (L) and the chelating The volume (mL) of the synthetic resin was calculated by the following formula. The total amount of metal impurities (μg/mL-R) = (the amount of each metal impurity (μg/L) × the volume of the eluent (L)) / the volume of the chelating resin (mL)

In addition, the above-mentioned total metal impurity amount is the chelate resin of 5 μ g/mL-R or less, for example, can obtain the method described in patent document 3. That is, it is a method of purifying by contacting the chelate resin with a mineral acid solution with a metal impurity content of 1 mg/L or less and a concentration of 5% by mass or more. Thereby, the total amount of metal impurities (especially the amount of dissolved metals such as Na, Ca, Mg, Fe, etc.) dissolved when the hydrochloric acid with a concentration of 3% by mass is passed through the chelating resin in an amount 25 times the volume ratio can be reduced to 5 μg/mL- R below. By using the chelating resin with reduced metal impurity content to carry out the refining of the hydrolyzable organic solvent, a high-purity hydrolyzable organic solvent containing less metal impurity can be obtained. As the inorganic acid solution, hydrochloric acid, sulfuric acid, nitric acid, etc. can be used. In addition, when the above-mentioned purification is performed using a Na-form chelate resin, the ionic form is converted to the H-form by performing the above-mentioned purification.

(anion exchange resin) As above-mentioned, in this invention, a cation exchange resin and a chelate resin can be mixed arbitrarily and used, but an anion exchange resin can also be combined further. By using anion exchange resin, acid generation can be reliably suppressed. Therefore, for example, even when only a cation exchange resin is used, or when there is a possibility of generating other acids, the generation of an acid can be further suppressed by using an anion exchange resin in combination. When using an anion exchange resin, the usage-amount of this anion exchange resin can be 0.1-100 volume% with respect to the total amount of a cation exchange resin and arbitrary chelate resin, for example.

Examples of anion exchange resins include strongly basic anion exchange resins having quaternary ammonium groups and weakly basic anion exchange resins having 1st to 3rd amine groups. Anion exchange resins include, for example: ORLITE (registered trademark) DS-2 (gel-type strongly basic anion-exchange resin, trade name, manufactured by Olucano Co., Ltd.), DS-5 (MR-type strongly basic Anion exchange resin, trade name, manufactured by Olucano Co., Ltd.), DS-6 (MR type weakly basic anion exchange resin, trade name, manufactured by Olucano Co., Ltd.), etc., but not limited to these . Among these, MR type anion exchange resins are preferable.

Before being used to purify hydrolyzable organic solvents, cation exchange resins, arbitrary chelating resins, and arbitrary anion exchange resins (hereinafter collectively referred to as "ion exchange resins") can also be subjected to pre-suppression of water elution from the resins. deal with. That is to say, in the refining method of the present invention, before the refining step, there may also be a pretreatment step, and the pretreatment step is carried out for cation exchange resin, any chelating resin and any anion exchange resin in order to inhibit the Pre-treatment for the resin to dissolve water.

The pretreatment method includes, for example, contacting a hydrolyzable organic solvent to be purified with an ion exchange resin, or contacting an ion exchange resin with an organic solvent for pretreatment that has a higher relative dielectric constant at 25°C than the hydrolyzable organic solvent to be purified. Methods. Specifically, the following method can be enumerated: In the column filled with the ion exchange resin before purification, the hydrolyzable organic solvent to be purified is passed through, and the liquid is continuously passed until the water concentration in the solvent is below the inlet of the column. Until it becomes the same level as export. The following method can also be enumerated: in the column filled with the ion exchange resin before the purification, the pretreatment organic solvent whose relative dielectric constant is greater than the hydrolyzable organic solvent of the purification object at 25 ° C is passed, and continuously Pass the liquid until the water concentration in the solvent becomes the same level at the inlet and outlet of the column. In this case, after passing the pretreatment organic solvent, the hydrolyzable organic solvent to be purified may be passed until the water concentration in the solvent becomes the same level at the inlet and outlet of the column. As the organic solvent for pretreatment, it is preferable to use alcohols such as methanol and ethanol with a relative dielectric constant of 20 or more at 25°C.

As another pretreatment method for suppressing elution of water from the resin, a method of setting a heat-resistant container filled with an ion exchange resin in a drier and performing a heat (dry) treatment for several hours is mentioned. Drying conditions can be set according to the type of ion exchange resin, and the appropriate temperature and time can be set between 50°C~120°C and 1 hour~24 hours. By performing this treatment, the water content in the ion exchange resin can be reduced to 10% by mass or less. The drying method may be any one of normal pressure, reduced pressure and vacuum drying, and from the viewpoint of short drying time and good efficiency, reduced pressure or vacuum drying is preferable. In addition, the water content of the ion exchange resin can be calculated using the following formula. Moisture content (mass %)=((mass of resin heat-treated with a dryer (g)-mass of resin completely dried with a heat-drying moisture meter (g))/resin heat-treated with a dryer Mass (g))×100

Here, in the above formula, the resin heat-treated with a dryer can be obtained by heat-treating the resin as described above (moisture content is 10% by mass or less). Then, the resin heat-treated in a dryer was stored and moved so as not to mix in moisture from the air until the heat-drying type moisture meter was used to measure the resin. Then, the resin was set on a heat-drying moisture meter, and the resin was completely dried at 105° C. for several minutes to tens of minutes to obtain a resin completely dried by the heat-drying moisture meter. As the heat drying type moisture meter, for example, MX-50 (trade name) manufactured by A&D Co., Ltd. can be used. In addition, in order to improve the accuracy of measurement, more than 5g of resin before drying is used for measurement.

The method of bringing the hydrolyzable organic solvent into contact with the ion exchange resin is not particularly limited, and examples thereof include a batch treatment method and a continuous liquid-passing treatment method using a column. Among them, the continuous liquid flow treatment method is preferable from the viewpoint of operability and efficiency.

In the continuous liquid treatment method, the ion exchange resin is filled in a purification column such as a column. The height of the resin packed bed in the refining tower is not particularly limited, and may be, for example, 100 to 1500 mm. Next, for example, 2-100 BV of a hydrolyzable organic solvent is introduced at a SV (space velocity, h ^-1 ) of 2-20. Here, BV (Bed volume) represents the flow rate of the solvent that is passed through relative to the amount of resin. From the standpoint of metal removal, the flow of the hydrolyzable organic solvent should be carried out at SV2~20, more preferably at SV5~10. The direction of the liquid flow can be either downflow or upflow. By passing the liquid in this way, metal impurities in the hydrolyzable organic solvent can be adsorbed to the ion exchange resin and removed.

Next, the batch processing method will be described. First, the ion exchange resin is filled in the reaction tank equipped with a stirrer. Then, the hydrolyzable organic solvent is filled in this reaction tank. The volume ratio is not particularly limited, but is preferably 2 to 200 of the organic solvent relative to the resin amount of 1. After that, it is left to stand, for example, for about 0.5 to 24 hours. After standing, run the mixer to mix the resin and the organic solvent evenly. The stirring speed and stirring time can be appropriately determined according to the size of the reaction tank, the processing capacity, and the like. After the stirring is completed, filter or the like is performed to separate the resin from the hydrolyzable organic solvent, thereby removing metal impurities and obtaining a refined hydrolyzable organic solvent.

In addition, regarding the ion exchange resin, before it is used to purify the hydrolyzable organic solvent, the above-mentioned pretreatment for suppressing the elution of water from the resin can be carried out, and the ion exchange resin can be contacted and hydrolyzed directly using the container such as the column used in the pretreatment. Non-toxic organic solvents are used for refining steps.

The refining method of the present invention mainly carries out the refining of the hydrolyzable organic solvent with continuous operation, that is, in the refining step, after the refining (fluiding) of the hydrolyzable organic solvent to be refined is started, the flow is not stopped until the end of the refining process. liquid and continuously. However, it is also possible to refine the hydrolyzable organic solvent by intermittent operation. When the purification of the hydrolyzable organic solvent is carried out by intermittent operation, in the test system, the organic solvent may be hydrolyzed by external moisture or functional groups from the resin to generate moisture and acid. Therefore, in the case of intermittent operation, the refining method of the present invention preferably has a discharge step, which is to discharge the cation exchange resin, any chelating resin, and any anion from the cation exchange resin, any chelating resin, and any anion for a fixed period of time after the start of the refining step. The hydrolyzable organic solvent eluted from the outlet of the purification tower for exchanging resin is discharged to the outside of the storage tank for storing the purified hydrolyzable organic solvent. For example, in the case of stopping the introduction of the hydrolyzable organic solvent for more than 30 minutes after the start of the purification step, as a discharge step, the amount relative to the ion exchange resin (cation exchange resin, any chelating resin, and any anion exchange resin) is After 0.5 BV or more of the hydrolyzable organic solvent eluted from the outlet of the purification tower is discharged to the outside of the storage tank, the purification step is started again. Water and acid generated during shutdown can be reduced by providing a drain step. The discharge amount (amount of hydrolyzable organic solvent discharged outside the system) in the discharge step can also be set in advance according to the stop time of operation, the water content in the hydrolyzable organic solvent in the outlet of the refining tower, the acid concentration, and the resistivity. Or it can also be set by online monitoring, and automatically stop the discharge step and switch to the refining step when the preset resistivity is reached. In addition, in the case where the purification of the hydrolyzable organic solvent is carried out by continuous operation, the above-mentioned discharge step may be implemented as required.

According to the purification method of the present invention, since acid generation from the hydrolyzable organic solvent is suppressed, the pH of the hydrolyzable organic solvent after the purification step can be kept near neutral. Specifically, the pH of the hydrolyzable organic solvent after the purification step can be adjusted to 5-7. However, depending on the type of the hydrolyzable organic solvent, the pH may be, for example, 4 or less.

According to the refining method of the present invention, in the refining step, the concentration of each metal in the hydrolyzable organic solvent can be reduced by at least 70% by mass, preferably at least 80% by mass. In addition, the metal impurities contained in the hydrolyzable organic solvent include, for example: Li, Na, Mg, Al, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ag , Cd, Sn, Ba, Pb, etc.

The following examples illustrate the present invention in detail, but the present invention is not limited to these examples. [Example]

The measurement methods of metal concentration, acetic acid concentration and moisture concentration are as follows.

(metal concentration) The metal concentration (ng/L) was measured using an Agilent 8900 three-stage quadrupole ICP-MS (trade name, manufactured by Agilent Technologies Co., Ltd.).

(acetic acid concentration) The acetic acid concentration (ppm by mass) was measured using a capillary electrophoresis system (trade name: Agilent 7100, manufactured by Otsuka Electronics Co., Ltd.).

(moisture concentration) The water concentration was measured by the Karl Fisher method using a Karl Fisher volumetric moisture meter (trade name: Aquacounter AQ-2200, manufactured by Hiranuma Sangyo Co., Ltd.).

(ion exchange resin) The details of the various ion exchange resins used in the following examples are as follows. ･ORLITE (registered trademark) DS-21 (trade name, manufactured by ORLITE Co., Ltd.): chelating resin, chelating group: aminomethylphosphonic group ･ORLITE (registered trademark) DS-4 (trade name, manufactured by ORLITE Co., Ltd.): MR type strongly acidic cation exchange resin, ion exchange group: sulfonic acid group ･ORLITE (registered trademark) DS-1 (trade name, manufactured by ORLITE Co., Ltd.): gel-type strongly acidic cation exchange resin, ion exchange group: sulfonic acid group, degree of crosslinking: standard ･AMBERLITE (registered trademark) CR99 K/350 (trade name, manufactured by DuPont): gel-type strongly acidic cation exchange resin, degree of cross-linking: low ･AMBERLITE (registered trademark) IRN99H (trade name, manufactured by DuPont): gel-type strongly acidic cation exchange resin, degree of cross-linking: high ･ORLITE (registered trademark) DS-6 (trade name, manufactured by Orlite Co., Ltd.): MR type weakly basic anion exchange resin

[Comparative Example 1, Examples 1 to 5: Comparison of Mixed Bed Ratio] (refinement of PGMEA) In a column made of PFA resin (inner diameter: 16 mm, height: 300 mm), the mixed bed ratio (volume ratio) of the cation exchange resin shown in Table 1 was filled with chelating resin so that the total amount was 36 mL. ORLITE (registered trademark) DS-21 and ORLITE (registered trademark) DS-4 which is an MR type strongly acidic cation exchange resin. In addition, it was confirmed that the total amount of metal impurities eluted when the hydrochloric acid with a concentration of 3% by mass was passed through the above-mentioned chelate resin in an amount of 25 times the volume ratio was 5 μg/mL-R or less. As a pretreatment, pass SV5 into PGMEA (trade name: PM Thinner, manufactured by Tokyo Ohka Industry Co., Ltd.) until the water concentration in PGMEA becomes the same level at the column inlet and column outlet to remove the resin moisture in. In addition, it was also confirmed that the water in the resin can be removed by passing, for example, methanol, which has a relative dielectric constant greater than PGMEA at 25° C., instead of PGMEA during the above pretreatment. Then, 20BV of PGMEA was passed through the pretreated resin at SV5 to perform a refining step. Collect the PGMEA (stock solution) before refining and the PGMEA at the outlet of the column after refining, and measure the Cr concentration, acetic acid concentration and water concentration. The results are shown in Table 1. In addition, the generated acetic acid was within the measurement error range up to 5 mg/L (absolute value), that is, it can be considered that almost no acetic acid was generated. In addition, in each example, the concentration of Cr and acetic acid in the stock solution is different, which is due to the difference in batch numbers of the stock solution.

[Table 1] Comparative example 1 Example 1 Example 2 Example 3 Example 4 Example 5 Mixed bed ratio of cation exchange resin 0% 10% 20% 25% 33% 100% Cr Stock solution concentration (ng/L) 40 89 43 59 70 65 Concentration after refining (ng/L) 18.0 14.4 4.6 4.7 3.9 2.0 Removal rate (%) 55 84 89 92 94 98 Acetic acid Stock solution concentration (mg/L) 37 20 20 15 13 12 Concentration after refining (mg/L) 34 twenty one twenty two 19 18 twenty two Acetic acid produced (mg/L) none 1 2 4 5 10 moisture Stock solution concentration (mg/L) 37 79 43 55 55 55 Concentration after refining (mg/L) 47 74 33 56 47 76

As shown in Table 1, in Examples 1 to 5 where the mixed bed ratio of the cation exchange resin is 10% to 100%, the Cr concentration in the refined PGMEA is less than 15ng/L, which on the one hand suppresses the generation of acetic acid, on the one hand Removes metals with good efficiency. Especially in the embodiment 1～4 that uses chelating resin and cation exchange resin with mixed bed, substantially suppressed the generation of acetic acid. On the other hand, in Comparative Example 1 in which the mixed bed ratio of the cation exchange resin was 0%, that is, only the chelating resin was used, the Cr removal rate in the purified PGMEA was 55%, which shows that it did not sufficiently remove the metal.

[Example 6~7: According to the kind of strongly acidic cation exchange resin, the removal performance of Cr is compared] As the strongly acidic cation exchange resin mixed with the chelating resin (mixed bed ratio: 25% by volume), ORLITE (registered trademark) DS-1 (gel-type strongly acidic cation exchange resin, degree of crosslinking: standard) and AMBERLITE (registered trademark) CR99 K/350 (the strongly acidic cation exchange resin of gel type, degree of cross-linking: low, the person that the K form is converted into H form), in addition, with embodiment 3 identical Methods for the purification of PGMEA. Sampling of PGMEA (stock solution) before refining and PGMEA at the outlet of the column after refining, and measuring Cr concentration and water concentration. The results are shown in Table 2 together with Example 3.

[Table 2] Example 3 Example 6 Example 7 Strongly acidic cation exchange resin DS-4 (MR type) DS-1 (gel type) CR99 K/350 (gel type) Cr Stock solution concentration (ng/L) 59 65 59 Concentration after refining (ng/L) 4.7 12.6 14.5 Removal rate (%) 92 81 75 moisture Stock solution concentration (mg/L) 55 59 59 Concentration after refining (mg/L) 56 71 58

As shown in Table 2, it can be seen that DS-4, which is an MR-type strongly acidic cation exchange resin, is compared with DS-1, which is a gel-type strongly acidic cation-exchange resin, and a gel-type small particle size strongly acidic cation The exchange resin CR99 K/350 has particularly good metal removal performance.

[Embodiments 8-10: According to the difference of cross-linking degree, compare the generation of acetic acid] As a gel-type strongly acidic cation exchange resin mixed with a chelating resin (mixed bed ratio: 25% by volume), AMBERLITE (registered trademark) IRN99H (crosslinking degree: high) and ORLITE (registered trademark) DS-1 were used respectively. (Degree of cross-linking: standard) and AMBERLITE (registered trademark) CR99 K/350 (degree of cross-linking: low, K-shape converted to H-shape), in addition to the purification of PGMEA in the same manner as in Example 3 . Sampling of PGMEA (stock solution) before refining and PGMEA at the outlet of the column after refining to measure acetic acid concentration and water concentration. The results are shown in Table 3.

[table 3] Example 8 Example 9 Example 10 Gel type strongly acidic cation exchange resin IRN99H (cross-linking degree: high) DS-1 (degree of cross-linking: standard) CR99 K/350 (cross-linking degree: low) Acetic acid Stock solution concentration (mg/L) 15 13 18 Concentration after refining (mg/L) 14 twenty three 29 Acetic acid produced (mg/L) none 10 11 moisture Stock solution concentration (mg/L) 58 59 59 Concentration after refining (mg/L) 83 71 58

As shown in Table 3, it can be seen that among gel-type strongly acidic cation exchange resins, when a highly cross-linked resin is used, the generation of acetic acid can be reliably suppressed.

[Reference Example 1: Reduction of acetic acid by anion exchange resin] Purification of PGMEA was performed in the same manner as in Example 3 except that only ORLITE (registered trademark) DS-6, which is an MR-type weakly basic anion exchange resin, was used as the resin. Sampling the PGMEA (stock solution) before refining and PGMEA at the outlet of the column after refining to measure the concentration of acetic acid. The results are shown in Table 4.

[Table 4] Reference example 1 cation exchange resin DS-6 (weak alkaline) Acetic acid Stock solution concentration (mg/L) 15 Concentration after refining (mg/L) <5 Acetic acid produced (mg/L) none

As shown in Table 4, it was found that acetic acid contained in the stock solution can be removed by using an anion exchange resin. Therefore, it was found that by further using an anion exchange resin in combination with the cation exchange resin of the present invention and an optional chelate resin, purification of a hydrolyzable organic solvent that reliably suppresses the generation of acetic acid can be performed.

Claims (10)

A method for refining a hydrolyzable organic solvent, which has a refining step, which is to make any cation exchange resin mixed with a chelating resin contact a hydrolyzable organic solvent for refining; The volume ratio of the cation exchange resin is 10-100%. The method for refining a hydrolyzable organic solvent according to claim 1, wherein the water concentration in the hydrolyzable organic solvent before refining is 20-10000 mg/L. The method for refining a hydrolyzable organic solvent as claimed in claim 1 or 2, wherein before the refining step, there is a pretreatment step, and the pretreatment step is carried out for the cation exchange resin and any of the chelating resins to inhibit the chelating resin from the Resin dissolves moisture before processing; This pretreatment system makes this cation exchange resin and any this chelating resin contact the method for treating with organic solvent before the relative dielectric constant in 25 ℃ is greater than this hydrolyzable organic solvent, or by drying Machine makes the water content of the cation exchange resin and any of the chelating resins be reduced to below 10% by mass. The method for purifying a hydrolyzable organic solvent according to claim 1 or 2, wherein an anion exchange resin is further used in combination with the cation exchange resin and any of the chelating resins. The method for refining a hydrolyzable organic solvent according to claim 1 or 2, wherein the cation exchange resin is a strongly acidic cation exchange resin. The method for refining a hydrolyzable organic solvent as claimed in item 5, wherein the strongly acidic cation exchange resin is an MR type strongly acidic cation exchange resin. A method for refining a hydrolyzable organic solvent as claimed in claim 5, wherein the strongly acidic cation exchange resin is a gel-type strongly acidic cation exchange resin with a crosslinking degree of 16% to 24%. The method for purifying a hydrolyzable organic solvent according to claim 1 or 2, wherein in the purifying step, the concentration of each metal in the hydrolyzable organic solvent is reduced by 80% by mass or more. As the refining method of the hydrolyzable organic solvent of claim 1 or 2, it has a discharge step, and after the refining step starts, the cation exchange resin, any chelating resin and any anion are filled with a fixed time. The hydrolyzable organic solvent eluted from the outlet of the purification tower for exchanging resin is discharged to the outside of the storage tank for storing the purified hydrolyzable organic solvent. A method for manufacturing a resin used for refining a hydrolyzable organic solvent, characterized in that: There is a step of arbitrarily mixing the cation exchange resin and the chelating resin, and relative to the total amount of the cation exchange resin and any arbitrary chelating resin, the volume ratio of the cation exchange resin is 10-100%.