KR20130125387A - Treatment method for photoresist development wastewater - Google Patents

Abstract

A method for treating photoresist developing wastewater using a RO device, which does not need to neutralize the RO permeate with an alkaline agent, prevents or suppresses the blockage of the RO membrane due to slime, and can obtain a good quality RO membrane permeate. After the photoresist developing wastewater is brought into contact with the cation exchange resin without adjusting the pH, it is clarified by an MF membrane device or the like, and then passed through the reverse osmosis membrane device to obtain a membrane permeate.

Description

TREATMENT METHOD FOR PHOTORESIST DEVELOPMENT WASTEWATER}

The present invention relates to a method for treating photoresist developing wastewater, and more particularly, to a method for treating using a reverse osmosis membrane apparatus (RO apparatus).

In order to manufacture electronic components such as semiconductor devices, liquid crystal displays, and printed boards, a film of photoresist is formed on a substrate such as a wafer, light is irradiated through a pattern mask, and then unnecessary photoresist is applied by a developer. After dissolving and developing and further performing a treatment such as etching, the insoluble photoresist film on the substrate is peeled off. The photoresist has a positive type in which the exposed part is soluble and a negative type in which the exposed part is insoluble. As a developer of the positive photoresist, an alkaline developer is the mainstream. As a developer of a negative photoresist, an organic solvent developer is the mainstream, but an alkali developer may be used.

As the alkali developer, for example, tetraalkylammonium hydrooxide (TAAH), in particular tetramethylammonium hydrooxide (TMAH), is used. Wastewater (photoresist developing wastewater) discharged from such a developing step or a cleaning step after the development is usually a mixture of 10 to 20000 ppm of tetraalkylammonium ions and a mixture or condensation of a quinonediazide and a phenol novolak resin used as a resist. The resist stripper derived from various photosensitive resins, such as water (photolysis type | mold photoresist), is normally contained in the density | concentration of about 10-1000 ppm, respectively.

In Patent Literature 1, an acid is added to a photoresist developing waste solution to lower the pH to 2 to 6 to precipitate a photoresist, followed by concentrating tetraalkylammonium ions using a RO membrane, removing the precipitate, and ionizing the concentrate by ion exchange. To purify and recover TAAH.

Japanese Laid-Open Patent Publication 2002-253931

In the method of treating the photoresist developing wastewater described in the Patent Document 1, the acid is added to the photoresist developing wastewater to insolubilize the photoresist, supply it to the RO apparatus, and separate the membrane into concentrated and permeate water containing precipitates and TAAH. do. This conventional method has the following problems.

i) In order to add acid to the photoresist developing wastewater to bring the pH to 2 to 6, it is necessary to neutralize the RO permeated water with alkali, and an alkaline agent is required.

ii) Photoresist development Because of the high TAAH concentration in the wastewater, slime clogging tends to occur in the RO film.

iii) The addition of a slime inhibitor to the RO unit to prevent slime occlusion results in the incorporation of a slime inhibitor into the concentrated water and the inability to recover TAAH from the concentrated water. Therefore, it is impossible to prevent the blocking of the RO film by the slime inhibitor.

iv) Since the TAAH in the wastewater is high concentration, part of the TAAH penetrates the RO membrane and flows out into the permeate. For this reason, the water quality of treatment of RO permeate is low.

The present invention solves the above-mentioned conventional problems, does not need to neutralize the RO permeate with an alkaline agent, and prevents the blockage of the RO membrane due to slime, thereby preventing and suppressing RO membrane permeate of good quality RO membrane. It is an object to provide a method of treating photoresist developing wastewater using an apparatus.

In the method for treating the photoresist developing wastewater of the present invention, the photoresist developing wastewater is brought into contact with a cation exchange resin, followed by a filtration treatment, and then passed through a reverse osmosis membrane device to obtain a membrane permeate water.

The photoresist developing wastewater may be brought into contact with the cation exchange resin without performing a pH adjusting treatment for lowering the pH.

After contacting the photoresist developing wastewater with the cation exchange resin, the photoresist developing wastewater may be subjected to a biotreatment before the dewatering treatment.

The biological treatment tank is preferably a fluidized carrier or a carrier type of a rocking fixed bed carrier.

In the present invention, the photoresist developing wastewater is first contacted with a cation exchange resin, and TAAH such as TMAH in the wastewater is adsorbed to the cation exchange resin. When TAAH is adsorbed and separated from the wastewater, the pH of the water after cation exchange is lowered, and the photoresist precipitates. The precipitated photoresist is removed by a decontamination treatment, and the decontamination treatment water is supplied to the RO apparatus. And the permeated water of this RO apparatus is taken out as process water. Concentrated water is treated with concentrated water treatment means.

In this way, since the TAAH and the photoresist-removed water are supplied to the RO apparatus, the concentration of the TOC component flowing into the RO apparatus is low, and slime generation in the RO film is prevented or suppressed.

In addition, since the TAAH concentration in the RO water supply is low, no or almost TAAH leaks even in the RO permeate, and the water quality of the RO permeate becomes good. Moreover, in normal cases, pH of the said cation exchange resin treated water is about 5-8, and neutralization by an alkali chemicals is unnecessary.

TAA ⁺ can be collect | recovered by regenerating the cation exchange resin which adsorbed tetraalkylammonium ion (TAA ⁺ ).

By contacting the photoresist with the cation exchange resin and then biotreating before the degreasing treatment, the soluble organics are decomposed and the water quality of the RO permeate is improved.

By using the biological treatment tank as a carrier system of a fluidized bed carrier or a rocking type fixed bed carrier, blockage by photoresist precipitates is prevented.

1 is a block diagram illustrating Embodiment 1. FIG.
2 is a block diagram illustrating Comparative Example 1. FIG.
3 is a block diagram illustrating Comparative Example 2. FIG.
4 is a block diagram illustrating Embodiment 2. FIG.
5 is a block diagram for explaining the third embodiment.
6 is a block diagram for explaining the fourth embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

This invention aims at the photoresist image development wastewater containing TAAH. A resist agent consists of a resist polymer, a photosensitive agent, a solvent, and an additive. As a resist polymer, a novolak-type resin, a phenol resin, polyparahydroxy styrene resin is mentioned, for example. They are poorly soluble in water in the neutral pH range. The photoresist developing wastewater to be treated in the present invention contains the resist polymer.

Examples of TAAH include tetramethylammonium hydrooxide (TMAH), tetraethylammonium hydrooxide, tetrapropylammonium hydrooxide, tetrabutylammonium hydrooxide, methyltriethylammonium hydrooxide, trimethylethylammonium hydrooxide, dimethyldiethylammonium hydrooxide, Trimethyl (2-hydroxyethyl) ammonium hydrooxide, triethyl (2-hydroxyethyl) ammonium hydrooxide, dimethyldi (2-hydroxyethyl) ammonium hydrooxide, diethyldi (2-hydroxyethyl) ammonium hydro Oxide, methyl tri (2-hydroxyethyl) ammonium hydrooxide, ethyl tri (2-hydroxyethyl) ammonium hydrooxide, tetra (2-hydroxyethyl) ammonium hydrooxide and the like. Among these, when pH is 11 or less, it is preferable to insolubilize, and TMAH is especially preferable.

The TAAH concentration in the photoresist developing wastewater is usually about 200 to 30000 mg / l (100 to 150000 mg / l in TOC), but the present invention is sufficient if the wastewater has a TAAH concentration or TOC concentration in this range. Can be processed. The pH of this photoresist developing wastewater is often about 10 or more.

In the present invention, the photoresist developing wastewater is removed without adjusting the pH for lowering the pH, and after removing the turbidity component by filtration, for example, filtration by an UF membrane, or the like, if necessary, and then cationic. Contact is made with the exchange resin and TAA ⁺ is adsorbed onto the cation exchange resin. What is necessary is just to experimentally determine treatment conditions, such as SV, suitably according to TAAH density | concentration etc. in wastewater. Moreover, it is preferable to select the conditions by which the TOC density | concentration in water after contacting with a cation exchange resin will be about 1-20 mg / L or less.

By this cation exchange | exchange process, TAAH is removed and pH of water falls, and it becomes pH 4-9 especially about 5-8 normally. Therefore, at least a part, usually most of the photoresist contained in the waste water is insolubilized and precipitates.

Therefore, in the present invention, after the water containing the precipitate is subjected to biological treatment as it is or after being treated, the precipitate is treated to remove the precipitate. By biological treatment, soluble organics not removed in RO, UF, and the like are decomposed, and the water quality of RO permeate is improved. As a biological treatment method, the carrier system which does not generate | occur | produce occlusion by resist precipitates, such as a fluidized bed and a rocking-type stationary bed (for example, what fixed a part of support | carriers, such as a string form and a sheet form, in the tank), is preferable. As for pH at the time of biological treatment, about pH 4-9 which an organism is easy to breed is preferable.

As a means for this clarification treatment, an UF membrane apparatus, an MF membrane apparatus, a filtration apparatus, a flocculation precipitation apparatus, a precipitation apparatus, a flocculation flotation apparatus, a flotation apparatus, etc. are mentioned, A UF membrane apparatus or an MF membrane apparatus is preferable. In addition, a part of the resist to be precipitated is colloidal, and from the viewpoint of penetrating the MF membrane, an UF membrane having a fractional molecular weight of 500,000 or less, for example, 100,000 to 500,000, is preferable to the MF membrane.

It is preferable to set it as pH 4-9, and to precipitate a photoresist precipitate before this deposit treatment.

This water treatment process is supplied to a RO apparatus, and it isolate | separates into concentrated water and permeate water. Since the TAAH concentration in the feed water to the RO apparatus is low, there is little or no TAAH leak in the RO permeate, and the water quality of the RO permeate is good. In addition, since the TOC concentration in the RO water supply is low, slime generation of the RO film is also prevented or suppressed. For example, even if slime occurs, slime may be added to prevent slime. This slime inhibitor does not permeate a RO membrane and does not affect the water quality of RO permeate.

Since the photoresist component concentration of RO water supply is low, the pH of RO water supply is not specifically limited.

Regarding RO concentrated water, the wastewater treatment plant is treated.

TAA ⁺ adsorbed by the cation exchange resin can be recovered by regenerating the cation exchange resin.

Example

Hereinafter, an Example and a comparative example are demonstrated.

≪ Example 1 >

A photoresist developing wastewater (electronic component manufacturing process wastewater) having a pH of 11, a TOC concentration of 126 mg / l and a conductivity of 46 mS / m containing TAAH as TAAH was placed on a cation exchange resin (CER) column as shown in FIG. After passing through SV32, it passed through the MF membrane | membrane apparatus (HAWP by Millipore Co., Ltd.), and deposited. The pH of this MF membrane treated water was 5, and the neutralization treatment with a neutralizing agent was unnecessary. This MF membrane-treated water was supplied to a RO apparatus (ES-20, manufactured by Nitto Electric Co., Ltd.) to obtain permeate. Table 1 shows TOC concentrations and electrical conductivity of cationic exchange resin treated water, MF membrane treated water, and RO permeate water. Moreover, BOD of RO feed water (namely, MF film | membrane treated water) was 5.0 ppm or less, and MFF value was 1.04.

The MFF value is a value used as an index of membrane filterability (membrane fouling) of water (membrane feed water) to be subjected to membrane separation. The measuring method of this MFF value is as follows.

(i) The flocculation process by a ruler tester obtains 1000 ml or more of flocculation process water.

(ii) The flocculated treated water is allowed to stand for 30 minutes to precipitate flocculated floc.

(iii) The coagulated treated water of (ii) is gradually filtered from the supernatant on a No. 5A (5 μm pore) filter paper, and finally the aggregated floc is included to filter the total amount of coagulated treated water.

(iv) 1000 ml or more of the obtained filtrate is put into two measuring cylinders 500 ml each.

(v) 500 ml of the filtrate of the first measuring cylinder was filtered by a reduced pressure of 66 kPa (500 mmHg) using a nitrocellulose membrane filter having a pore diameter of 0.45 µm and a diameter of 47 mm. Measure the time T1 required. Subsequently, 500 mL of the filtrates of another measuring cylinder are filtered under reduced pressure similarly, and the time T2 required for the filtration at this time is measured.

(vi) The MFF value is calculated by the following formula.

MFF = T2 / T1

As the MFF value is closer to 1.00, it can be evaluated that the water is of good quality as the membrane feed water and the water is less likely to contaminate the membrane. Generally, MFF value 1.1 or less is said to be preferable as membrane feed water. For example, tap water (water from Nogimachi, Tochigi Prefecture) has an MFF of 1.03 to 1.06, an average of 1.05.

≪ Comparative Example 1 &

The same photoresist developing wastewater as in Example 1 was treated in the same procedure as in Patent Document 1.

That is, as shown in FIG. 2, after the wastewater was made to pH 6 by sulfuric acid, it was made to flow into the said MF membrane apparatus, and it was made to flow into the said RO apparatus. Table 1 shows TOC concentrations and electrical conductivity of RO water supply and RO permeate. Moreover, BOD of RO water supply was 77 ppm.

As described above, according to Example 1, it was confirmed that the TOC concentration and the BOD concentration of the RO feed water and RO permeate water were remarkable, the water quality of the RO permeate water was good, and the slime of the RO membrane was prevented as compared with Comparative Example 1. .

Comparative Example 2

As shown in Fig. 3, in Comparative Example 1, the photoresist developing wastewater was tried to be treated in the same manner except that the MF film was not deposited, but the RO film was blocked. The RO water supply of the comparative example 2 was inferior in membrane filterability so that MFF value could not be measured.

<Example 2>

As shown in Fig. 4, in Example 1, the photoresist developing wastewater was treated in the same manner except that the UF membrane having a fractional molecular weight of 300,000 was used instead of the MF membrane. As a result, the cleaning frequency of the RO membrane was sufficient once every nine months. In addition, in Example 1, the washing frequency of the RO membrane was once every three months. Therefore, it was confirmed that the UF membrane is preferable to the MF membrane than the MF membrane.

The TOC concentration of the RO permeate of Example 2 was 1.0 mg / L.

<Example 3>

As in FIG. 5, in Example 2, it treated similarly except having made UF membrane process, after biologically treating a cation exchange resin treated water. The biological treatment tank was in a fluidized bed mode. As a result, the TOC concentration of the RO permeate was 0.5 mg / l, which was lower than that in Example 2. This water permeate can be used for pure water production. This biotreatment tank was operated without occlusion for over two weeks.

<Example 4>

As in FIG. 6, the treatment was performed in the same manner as in Example 3 except that the biological treatment tank was not a fluidized bed biological treatment tank but a fixed bed biological treatment tank. In this case, a resist adhered to the biological support layer of the biological treatment tank, and the biological treatment tank was blocked in about two weeks.

While the invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.

In addition, this application is based on the JP Patent application (Japanese Patent Application No. 2011-064368) for which it applied on March 23, 2011, The whole is taken in into consideration.

Claims (6)

A method of treating photoresist developing wastewater, wherein the photoresist developing wastewater is brought into contact with a cation exchange resin, followed by a clarification treatment, followed by passing through a reverse osmosis membrane device to obtain a membrane permeate water. The method of claim 1,
A method for treating photoresist developing wastewater, wherein the photoresist developing wastewater is brought into contact with a cation exchange resin without carrying out a pH adjusting treatment for lowering pH. 3. The method according to claim 1 or 2,
A method of treating photoresist developing wastewater, wherein the photoresist is an insoluble substance at pH 11 or lower. The method according to any one of claims 1 to 3,
The method for treating photoresist developing wastewater, wherein the depositing means is an UF film. The method according to any one of claims 1 to 4,
A method of treating photoresist developing wastewater, wherein the treatment is carried out after contact with the cation exchange resin and before biological treatment. The method of claim 5, wherein
The biological treatment is performed using a fluidized bed carrier or a rocking type fixed bed carrier.

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