JP2011125770A - Method for recycling treated waste liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To contribute to a substantial disposal cost reduction and a production cost reduction by recycling, as industrial water, a treated waste liquid after recovering tetraalkylammonium ions by adsorption of the tetraalkylammonium ions from a development waste liquid containing the tetraalkylammonium ions, although the treated waste liquid has been heretofore discharged through appropriate treatment without being used. <P>SOLUTION: The treated waste liquid after the recovery of the tetraalkylammonium ions is recycled, for example, as industrial water in a process for recovering a tetraalkylammonium hydroxide from a liquid containing the recovered tetraalkylammonium ions and purifying the tetraalkylammonium hydroxide. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for reusing a processing waste liquid discharged when recovering a tetraalkylammonium hydroxide from a developing waste liquid containing tetraalkylammonium ions.

  In semiconductor and liquid crystal manufacturing processes, when forming a pattern on a substrate such as a wafer or glass, a negative or positive resist made of novolac resin, polystyrene resin or the like is applied to a metal layer formed on the substrate surface, This is exposed through the photomask for pattern formation, and the uncured portion or the cured portion is developed using a developer mainly composed of tetraalkylammonium hydroxide (hereinafter referred to as TAAH). Thereafter, a developing process is performed in which a pattern is formed on the metal layer by etching, and a developing waste solution containing tetraalkylammonium ions (hereinafter referred to as TAA ions) is discharged.

  In addition, after the development with the developer, a so-called rinse process is performed with ultrapure water in order to remove the developer remaining on the substrate. After the rinse process, a rinse waste liquid containing TAA ions is removed. Discharged. These development waste liquid and rinse waste liquid are usually mixed and then discharged as development waste liquid containing TAA ions. In recent years, as the production amount of semiconductors and liquid crystals increases, the consumption of the developer increases, and the discharge amount of the developer waste solution containing these TAA ions also increases. Recently, there has been proposed a method for recovering TAA ions containing TAA ions, which is recovered from TAAH containing TAA ions, purified and reused.

  The developer waste solution containing TAA ions discharged from the semiconductor and liquid crystal manufacturing process includes, in addition to TAA ions, a photoresist component such as novolak resin and polystyrene resin dissolved in the developer waste solution, and a trace amount of organic solvent, interface. It also contains organic substances such as activators (hereinafter simply referred to as organic substances), trace amounts of metal components eluted from the metal layer on the substrate surface and piping materials in the manufacturing process.

  Therefore, as a method for recovering the developer waste solution containing TAA ions, the developer waste solution containing TAA ions is brought into contact with the cation exchange material, and the TAA ions are adsorbed to the cation exchange material, so that the TAA ions in the developer waste solution are absorbed. A method of recovering TAA hydroxide by bringing the TAA salt into an electrochemical cell after bringing the acid into contact with the cation exchange material and then eluting the TAA salt is proposed (see Patent Document 1). ).

Special table 2002-509029

  In the method described in Patent Document 1, the concentration of TAA ions in the obtained eluent is increased by the adsorption and elution of TAA ions to the cation exchange material. For this reason, since the said process is performed also as concentration of TAA ion, it is the collection method with the high current efficiency in collection | recovery of TAA hydroxide by an electrochemical cell, and was excellent.

  However, since the development waste liquid containing TAA ions supplied to the cation exchange material usually has a very low TAA ion concentration of about 0.5% or less, the treatment waste liquid after the collection of TAA ions by the cation exchange material is used. The amount tends to increase.

  Since such processing waste liquid contains organic substances and metal components in the development waste liquid, it is considered that there is no effective recycling means and has been discharged through appropriate processing.

  However, with the increase in the discharge amount of developing waste liquid containing TAA ions, the discharge amount of the treatment waste liquid has also increased. From the viewpoint of reducing the costs associated with wastewater treatment, it is possible to establish a method for reusing the treatment waste liquid. It has been desired.

  The present invention has been made in view of the above situation. That is, an object of the present invention is to provide a method for reusing a processing waste liquid after recovering TAA ions by bringing a developing waste liquid containing TAA ions into contact with a cation exchange resin to adsorb the TAA ions. There is.

  In view of the above problems, the present inventors have conducted intensive studies. First, as a result of analyzing the content of impurities in the treatment waste liquid, the present inventors have found that it is highly pure water contrary to expectations. Therefore, as a result of studying the use of the above treatment waste liquid as industrial water, for example, when recovering TAA hydroxide as primary raw water in an ultrapure water production process or by supplying a liquid containing TAA ions to an electrolytic cell The present invention has been found out that it can be used as industrial water such as cooling water for electrolytic baths.

  That is, the present invention is to reuse the processing waste liquid after recovering TAA ions as industrial water by contacting the development waste liquid containing TAA ions with a cation exchange resin to adsorb the TAA ions. This is a method for reusing a processing waste liquid.

  Conventionally, the processing waste liquid after the TAA ions are brought into contact with the cation exchange resin and the TAA ions are recovered has been discharged through an appropriate process without being used. By this invention, it becomes possible to reuse the said processing waste liquid as industrial water, and can contribute to the drastic reduction of the cost concerning disposal, and the manufacturing cost reduction.

It is a flowchart which shows the typical processing method of this invention.

  The present invention is characterized by reusing the processing waste liquid after recovering TAA ions as industrial water by contacting the development waste liquid containing TAA ions with a cation exchange resin to adsorb the TAA ions. is there.

A typical processing method for recovering and purifying hydroxylated TAA from a developing waste solution containing TAA ions will be described with reference to the flowchart of FIG. The developer containing TAA ions is adjusted to an appropriate concentration with ultrapure water and used as a developer in the development process. The development waste solution containing TAA ions discharged through the development step and the rinsing step is brought into contact with a cation exchange resin to adsorb the TAA ions, whereby the TAA ions are recovered and the processing waste water is discharged. . The TAA ions adsorbed on the cation exchange resin are eluted from the resin with an acid and recovered as a solution containing TAA ions. The recovered solution is recovered as hydroxylated TAA in an electrolysis step (or anion exchange resin treatment (not shown)) through a purification step for concentration and removal of metal impurities, if necessary. In addition, the cation exchange resin used for the adsorption of TAA ions is regenerated with an acid adjusted to an appropriate concentration and reused for the adsorption of TAA ions in a developing waste solution containing TAA ions. <TAA ions Development waste liquid containing
The developing waste solution containing TAA ions used in the purification method of the present invention will be described in detail.

  In the present invention, the development waste liquid containing TAA ions refers to the waste liquid discharged from the development process and the rinsing process in the semiconductor and liquid crystal manufacturing process. The waste liquid is usually mixed with the waste liquid discharged from the development process and the rinsing process, and TAA ions contained in the waste liquid are recovered as hydroxylated TAA.

  In the present invention, specific examples of TAAH include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. Among the above TAAH, tetramethylammonium hydroxide can be suitably used because it is widely used as a developer in the semiconductor manufacturing process.

The concentration of TAA ions in the development waste solution containing TAA ions used in the present invention is not particularly limited, and development waste solutions having various TAA ion concentrations can be used. The concentration of TAA ions in the developer waste discharged in the development step is usually about 1.0 to 5.0%, but a large amount of rinse waste is generated in the rinse step and mixed with the developer waste. Therefore, the TAAH concentration in the developing waste liquid containing TAA ions discharged from the semiconductor and the liquid crystal manufacturing process is usually about 1% or less. The TAAH-containing developing waste liquid includes a metal layer or a metal layer in the semiconductor / liquid crystal manufacturing process. A trace amount of metal components eluted from the piping material are contained. The concentration of the metal component is, for example, about 0.1 to 50 ppb for the TAAH-containing developer waste discharged in the semiconductor manufacturing process, and about 1 to 100 ppb for the TAAH-containing developer waste discharged in the liquid crystal manufacturing process.

  In addition, as described above, the TAAH-containing developer waste solution includes organic substances derived from photoresist such as novolak resin and polystyrene resin dissolved in TAAH, and organic substances such as trace amounts of organic solvents and surfactants (hereinafter simply referred to as organic substances generically). Is dissolved). The concentration of the organic matter dissolved in the TAAH-containing developer waste having a TAAH concentration of 1% by mass or less is usually about several to several hundred ppm in terms of COD.

<Contact between developer waste solution containing TAA ions and cation exchange resin>
In the present invention, a developing waste solution containing TAA ions is brought into contact with a cation exchange resin. When the developer waste solution containing TAA ions is brought into contact with the cation exchange resin, the counter ions of the cation exchange resin and the TAA ions are exchanged, and the TAA ions are adsorbed on the cation exchange resin. As a result, TAA ions can be recovered from the developing waste liquid containing TAA ions.

  In the present invention, the cation exchange resin used is, for example, a styrene-divinylbenzene copolymer, an acrylic acid-divinylbenzene copolymer, a methacrylic acid-divinylbenzene copolymer or the like having a sulfonic acid group or the like. Examples include strongly acidic cation exchange resins having strong acid groups introduced therein, and weakly acidic cation exchange resins having weak acid groups such as carboxyl groups and phenolic hydroxyl groups introduced into the substrate. As the structure of the resin, there are a gel type, a porous type, a high porous type, and a macroreticular (MR) type. In the present invention, any of these structures can be preferably used. In particular, the MR type excellent in swelling shrinkage strength is suitable.

The cation exchange resin is usually marketed with hydrogen ions (H type) or sodium ions (Na type) as counter ions, but when Na type cation exchange resin is used, TAA ions and By the ion exchange, Na ions are discharged, and there is a tendency that Na ions in the treatment waste liquid after recovering TAA ions increase. Therefore, it is preferable to use H type as the cation exchange resin. In addition, when using the cation exchange resin marketed by Na type, what is necessary is just to let acids, such as hydrochloric acid and a sulfuric acid, flow beforehand through a cation exchange resin, and use a counter ion as a hydrogen ion.

  In addition, the H-type cation exchange resin and the cation-exchange resin in which the Na type is converted to the H type by acid should be sufficiently washed with ultrapure water before contacting the developer waste solution containing TAA ions. Is preferred.

  From the viewpoint of preventing Na ions from being mixed into the treatment waste liquid, it is preferable that the amount of sodium elution in the water discharged from the cation exchange resin is 100 ppb or less when washing with ultrapure water. When the amount of sodium elution in water is 100 ppb or more, the above acid replacement with H-type by passing the solution and washing with ultrapure water may be performed until the amount of sodium elution in water becomes 100 ppb or less. .

  Moreover, a well-known method can be suitably employ | adopted about the method of making the waste liquid containing TAA ion and cation exchange resin contact. Specifically, for example, a column system in which a column is filled with a cation exchange resin and the waste liquid is continuously passed through, a cation exchange resin is added to the waste liquid and brought into contact with stirring, and then filtered. A batch system for solid-liquid separation can be employed. Among these, in consideration of operability, it is preferable to adopt the column method. When this column method is adopted, it may be determined as appropriate according to the performance of the cation exchange resin, etc., but in order to adsorb TAA ions efficiently, a waste liquid having a TAAH content of 0.001 to 1% by mass. If so, the ratio (L / D) of the column height (L) to the diameter (D) is 0.5 to 20, and the space velocity (SV) of the waste liquid is 5 (1 / hour) or more 50 (1 / Hour) or less.

  The amount of the waste liquid containing TAA ions to be brought into contact with the cation exchange resin is preferably performed until the exchange capacity of the cation exchange resin is reached, in order to prevent the mixing of the TAA ions into the treatment waste liquid. Regarding the concentration of TAA ions in the treatment waste liquid, the treatment waste liquid discharged from the cation exchange resin can be analyzed by ion chromatography.

<Recovery of TAA ions>
TAA ions adsorbed on the cation exchange resin can be eluted by contacting the resin with an acid. The acid brought into contact with the cation exchange resin is not particularly limited as long as hydrogen ions are generated in an aqueous solution state, and examples thereof include aqueous mineral acid solutions such as hydrochloric acid and sulfuric acid. Of the above acids, an aqueous hydrochloric acid solution is most preferred because it is industrially inexpensive and can be obtained, and the concentration can be easily adjusted. The concentration and use amount of the hydrochloric acid are not particularly limited as long as the concentration and amount are sufficient to elute the adsorbed TAA ions. Usually, the cation exchange resin is 1 to 10% by mass hydrochloric acid aqueous solution. It is sufficient to contact 1 to 10 (L / L-resin).

<Reuse of processing waste liquid>
The waste treatment solution containing TAA ions is brought into contact with a cation exchange resin to adsorb the TAA ions, so that the treatment waste solution after recovering TAA ions has a pH of about 4.0 to 9.0 and the total amount of metal ions. It is relatively high-purity water containing about 1 to 200 ppb of organic matter in an amount of about 1 to 200 ppm in terms of COD. The present invention is characterized by reusing such treatment waste liquid as industrial water. In the present invention, the treatment waste liquid can be reused as it is as described later, but depending on the purpose of use, an appropriate post-treatment (for example, the pH of the treatment waste liquid by addition of acid or alkali) It is also possible to use it after adjusting).

  The processing waste liquid in the present invention is diluted with developer concentration adjusting dilution water (reuse i), rinse water in the rinse step (reuse ii), and acid concentration adjustment dilution used in the regeneration of the cation exchange resin in FIG. Water (reuse iii), concentrator cooling water in the concentration process (reuse iv), cleaning water in the purification process (reuse v), electrolytic bath cooling water, or makeup water (reuse vi), and other utilities It can be reused as water (reuse viii).

  In addition, as described above, the treatment waste liquid of the present invention is relatively high-purity water, and thus can be used as raw water for producing ultrapure water (reuse vii).

  In order to describe the present invention specifically, the present invention will be described below with reference to examples. However, the present invention is not limited to these examples.

  The concentration of tetramethylammonium hydroxide (hereinafter referred to as TMAH) -containing waste liquid discharged from the liquid crystal factory is adjusted to a concentration (0.05% in Example 1, 0.5% in Example 2). The prepared waste liquid was used as a sample liquid. Table 1 shows the water quality of the sample solution.

  The pH is measured by the pH electrode method (measuring device: HM-30R (manufactured by Toa DK Corporation)), the TMA ion concentration is measured by the ion chromatograph method (measuring device: DX320 (Dionex)), and the metal concentration is induced by high frequency. COD was analyzed by oxygen consumption (JIS K 0101) by potassium permanganate at 100 ° C. by a coupled plasma emission analysis (ICP-OES) method (measuring device: iCAP 6500 DUO (manufactured by Thermo Electron Co., Ltd.)).

Example 1
100 ml of weakly acidic cation exchange resin DIAION WK40L (manufactured by Mitsubishi Chemical Corporation) is packed in a glass column having a diameter of 2.2 cm, and 1N hydrochloric acid is used with a space velocity of 6 L / L-resin · hr (600 ml / hr: SV). = 6), 800 ml of liquid was passed through to regenerate the resin into H type. Next, hydrochloric acid remaining in the resin was washed with ultrapure water.

  40,000 ml of sample solution (TMAH concentration 0.05%) was passed through the column at a space velocity of 40 L / L-resin · hr (4,000 ml / hr: SV = 40) with respect to the amount of resin. Adsorption was performed. As a result of recovering the treatment liquid after adsorption of TMA ions and analyzing the water quality, no TMA ions were detected. Table 1 shows the water quality of the treatment waste liquid.

Example 2
100 ml of weakly acidic cation exchange resin DIAION WK40L (manufactured by Mitsubishi Chemical Corporation) is packed in a glass column having a diameter of 2.2 cm, and 1N hydrochloric acid is used with a space velocity of 6 L / L-resin · hr (600 ml / hr: SV). = 6), 800 ml of liquid was passed through to regenerate the resin into H type. Next, hydrochloric acid remaining in the resin was washed with ultrapure water.

  4,000 ml of sample solution (TMAH concentration 0.5%) was passed through the column at a space velocity of 40 L / L-resin · hr (4,000 ml / hr: SV = 40) with respect to the amount of resin. Adsorption was performed. As a result of recovering the treatment liquid after adsorption of TMA ions and analyzing the water quality, no TMA ions were detected. Table 1 shows the water quality of the treatment waste liquid.

  As is clear from Examples 1 and 2 above, the processing waste liquid after recovering TAA ions by contacting the development waste liquid containing TAA ions with a cation exchange resin to adsorb the TAA ions is high. Purity water. Therefore, this processing waste liquid can be reused as the water.

Claims (6)

  The developer waste solution containing tetraalkylammonium ions is brought into contact with a cation exchange resin to adsorb the tetraalkylammonium ions, thereby reusing the processing waste solution after recovering the tetraalkylammonium ions as industrial water. A method for reusing processing waste liquid, which is characterized.   The method for reusing a processing waste liquid according to claim 1, wherein the ion form of the cation exchange resin is a hydrogen ion form.   The method for reusing a processing waste liquid according to claim 1, wherein the sodium elution amount of the cation exchange resin is 100 ppb or less.   The method for reusing a treatment waste liquid according to claim 1, wherein the treatment waste liquid has a tetraalkylammonium ion concentration of 50 ppm or less and a total metal ion concentration of 10 ppm or less.   The method for reusing a processing waste liquid according to claim 1, wherein the processing waste liquid is used as at least a part of a rinsing liquid used in a rinsing step in a development step.   The method for reusing a processing waste liquid according to claim 1, wherein the processing waste liquid is used as cooling water.

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