JPS6331591A - Treatment of photoresist waste liquid - Google Patents

Abstract

PURPOSE:To attain repeated utilization, by separately subjecting a waste developing solution and a release waste solution to ultrafiltration and reutilizing both transmitted solutions. CONSTITUTION:A waste developing solution and a release waste solution are separately subjected t ultrafiltration and concentrates flowing out are mixed to be treated. The photoresist components dissolved in an aqueous alkali solution are insolubilized with the reduction of the OH<-> ion in water. Subsequently, dehydration treatment is performed to remove dehydrated sludge and the liquid component is filtered. In a final process, treatments such as reverse osmosis, decomposition by ultraviolet rays, adsorption by activated carbon, biological treatment or the like are performed. An ultrafiltration membrane pref. has fractionation MW of 5,000-10,000. By this method, the treatment cost of both waste solutions can be markedly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for treating waste liquid discharged from a printed circuit board manufacturing process. Especially waste liquid! The present invention relates to a method for treating waste liquid that can be recycled using an IJ method and used repeatedly as a developer or stripping liquid.

[Conventional technology] With conventional waste liquid treatment technology for printed circuit board manufacturing.

None of these methods takes into account the recovery of waste liquid, and assumes that the entire amount of detection will be processed. The developing waste liquid and stripping waste liquid discharged from the printed circuit board manufacturing process are alkaline waste liquids in which a water-soluble photoresist resin and an antifoaming agent are dissolved.2 They contain a high concentration of photoresist resin and have a high COD, e.g. 500.
0~lO100OO/l, or high BoD e.g. 1
1000-3000ffI/lノ(II
7), and therefore the waste liquid treatment cost was extremely high.

Conventionally, this treatment method includes one using acid-biological-activated carbon and the other using reverse osmosis.
There are the following problems. In the former case, the efficiency of biological treatment is low and the COD removal rate is less than 50%. Specifically, it is difficult to decompose biologically, the pollutant load on activated carbon is large, raising the treatment cost, a large amount of dilution water is required, tens of times the amount of waste liquid, and acid addition and A large amount of chemicals can be consumed through Japanese processing,
Biological treatment requires a large tank, which requires a large installation area, and the treatment cost is enormous.

In addition, in the latter case, the waste liquid discharged from printed circuit board manufacturing contains about 2% inorganic substances, so it has a high a
The practical limit is that the reduction ratio cannot be ensured, that is, the degree of concentration is 5 times due to an increase in osmotic pressure. Therefore, about 115 ml of concentrated liquid waste remains to be treated.

[Problems to be Solved by the Invention] The developing waste liquid and stripping waste liquid discharged in printed circuit board manufacturing are alkaline waste liquids in which water-soluble photoresist resin, antifoaming agent, etc. are dissolved, and they have high COD and BOD. Waste liquid treatment costs are also high. On the other hand, the developer is costly! 1. Previously, the entire amount of syneresis was disposed of. In contrast, it is an object of the present invention to provide a waste liquid treatment method with reduced waste liquid treatment costs. Also, developer.

The purpose of the present invention is to provide a waste liquid treatment method that allows the separation liquid to be reused.

[Means for Solving the Problems] The present invention provides a method for treating developer waste liquid or 11) waste liquid discharged from a printed circuit board manufacturing process.

A photoreceptor characterized in that a developer waste solution or a stripping waste solution containing a photorenost resin, an antifoaming agent, etc. is separately subjected to ultrafiltration, and the solution that passes through the ultrafiltration membrane is repeatedly reused as a developer solution or a stripping solution, respectively. This is a method for treating resist waste liquid.

[Operations] In the conventional waste liquid treatment method, the entire amount of waste liquid is treated, but in the waste liquid treatment method according to the present invention, the amount of waste liquid is concentrated to about 1/10 to 1/20 by ultrafiltration, and the concentrated liquid is By performing neutralization, dehydration, filtration, and finishing treatments, the amount of waste liquid to be treated can be reduced. Therefore, in the final process, the amount of waste liquid to be discharged and disposed of, for example, by reverse osmosis, is (1/
10~1/20)
It becomes possible to reduce the amount to a certain extent. Furthermore, most of the alkaline agents and antifoaming agents in the developer waste solution and stripping waste solution can be recovered and reused.

A waste liquid treatment system according to the present invention is shown in FIG.

Conventionally, various waste liquids discharged from the development and peeling processes of printed circuit board manufacturing have been mixed and treated by the method shown in FIGS. 2 and 3. The acid-biological-activated carbon treatment method (Figure 2) combines the developer waste and stripping waste.

Make the alkaline acidic by adding acid, add a flocculant, flocculate, dehydrate, remove dehydrated sludge, neutralize the wash dilution water with NaOH, first, biologically treat, precipitate, and remove the sludge. The precipitated filtrate is further filtered and adsorbed on activated carbon, and the clean water is discharged. As mentioned above, this treatment method is inefficient, has a large pollutant load on activated carbon, tends to be expensive, and requires acid addition.
Large amounts of chemicals are required, including the addition of neutralizing agents.

In the reverse osmosis method shown in Figure 3, the developer waste solution and stripping waste solution are combined, filtered, and then concentrated by reverse osmosis method.
The permeate was neutralized with sulfuric acid, etc., diluted, and discharged. Here, as mentioned above, the problem is the treatment of the concentrated liquid, which has an amount of about 115% of the deep waste liquid.In contrast, in the waste liquid treatment method of the present invention, the developing and stripping waste liquids are each kept alkaline, while
Through the ultraviolet membrane, it is exposed to aphrodisiacs. In the development waste solution, the photorenost resin component does not pass through the ultra-a filtration membrane, but remains as an a-condensed solution and is discharged out of the recovery system, while the ultra-filtration membrane permeate is returned as a developer and used again. be. In addition, in the treatment of stripping waste liquid, the liquid that has passed through the ultrafiltration membrane is recycled to be used again as a stripping solution.

The concentrated liquid that can be separated by this ultrafiltration membrane can be reduced to 1/10 to 1/20 of the amount of waste liquid.

The conditions that enable the treatment of printed circuit board manufacturing waste liquid according to the present invention are that the module characteristics of the ultrafiltration membrane and the components of the waste liquid must be appropriate. It must meet the conditions.

First, the ultrafiltration membrane module must be alkali-resistant because the photoresist waste liquid to be treated is alkaline.

Secondly, the molecular weight cutoff of the ultrafiltration membrane is preferably in the range of 5,000 to 10,000 in order to pass through the inorganic matter dissolved in the alkaline waste liquid and remove the photoresist component. At this time, the concentration of suspended solids in the waste liquid was 10,000 mg/
Up to l is allowed.

This N range was determined by taking into consideration the characteristics of the actual photoresist development waste solution and stripping waste solution for the photoresist waste solution treatment method according to the method of the present invention. That is, an ultrafiltration membrane generally has a molecular weight fractionation characteristic that removes solutes within a certain molecular weight range, but in addition to this characteristic, it also has a molecular weight fractionation characteristic that removes solutes within a certain molecular weight range. The results of measuring the removal performance for inorganic alkaline agents are shown in Figure 4. Here, the removal rate corresponds to the reduction rate in the membrane permeate liquid relative to the raw solution supplied for membrane treatment. It is the ratio of ingredients. Figure 4 shows (
1) Development waste without antifoaming agent, ie.

1wt% Na+co+y photoresist 0,2 at night
m'/1 Removal rate of photoresist component in completely dissolved solution A (removal waste solution without antifoaming agent, i.e., 2% by weight of KO)
B/& photoresist 0.3m”/1 completely dissolved in H solution
Removal rate of the photoresist inside, 0) Removal rate of antifoaming agent component of liquid C containing antifoaming agent (polyalkylene gellicol), (
4) The graph shows the removal rate of fa components such as soda (NaHCO1, NaOH, etc.) in solution D containing 1% by weight of Na+CO- and the removal rate of KOH components in solution E (containing 92% by weight of KOH). From this graph.

It can be seen that the range in which nearly 100% of the photorenost component can be removed and most of the antifoaming agent and alkali components can be recovered is when the 2 molecular weight fraction is in the range of 5000 to toooo. It is an active ingredient in the developing waste solution and the cleaning waste solution from photoresist processing.

It is economical to recover as much of the antifoaming agent and alkaline components as possible. On the other hand, it is necessary to remove as much of the photoresist component as possible to maintain high photoresist dissolving performance of the regenerating solution. From these points, the range of characteristics of the ultrafiltration membrane according to the present invention was determined as described above.

The Ultra 111 membrane module that meets this condition is:

Among synthetic polymer materials, for example, polysulfone, polyimide, acrylonitrile, etc. are suitable as membrane materials. Also, what is the format of the module?

Tubular type is preferred.

To develop the photoresist used in the manufacture of printed circuit boards after exposure, the developer used in the development process to remove the photoresist, the developer waste to be treated, and the ultrafiltered solution. Table 1 shows the properties of the stripping solution used to strip the photoresist that has been photopolymerized after etching conductor plates, etc. in the manufacture of printed circuit boards, its stripping waste solution, and the solution subjected to extreme conditions.

According to the present invention, in order to process the developer waste liquid by ultrafiltration and use the developer that has passed through the ultrafiltration membrane as a developer again in the development process, the alkali component is consumed in the previous development process. Since the pH value has decreased, alkaline solution is replenished to the liquid passing through the outer membrane to adjust the pH.
In addition, the pH of the stripping solution is similarly adjusted, and the liquid passing through the ultrafiltration membrane is returned as the stripping solution.

If, Na+CO, to adjust the pH+7) of the regenerated developer.
, replenish the NaOH solution. When Na ions in the developer increase,! There is a risk that even the photoresist that should be dissolved in the 411 step may be dissolved.However, in the method of the present invention, the Na and CO8 replenishment amounts can be set in accordance with the membrane concentrated waste liquid.
Accumulation of ions can be prevented.

It is sufficient to adjust the components of the regenerated stripping solution by adjusting the pH to about 14 with a NaOH or KOH solution.

The a-glue solution discharged from both the development and stripping steps and concentrated through ultraviolet a-filtration is discharged to the outside of the two-recovery system and processed as shown in FIG.

When treating both the developing waste liquid and the stripping waste liquid, the concentrated liquids from the ultrafiltration of each system are mixed and treated. The photoresist component dissolved in the alkaline aqueous solution is
It becomes insolubilized as H- ions decrease. It is connected to the above-mentioned recovery system according to the present invention, subjected to acid addition treatment, then dehydration treatment, removal of dehydrated sludge, and filtration. These series of treatments utilize the properties of two or more photoresist components. The final step can be carried out by reverse osmosis, ultraviolet decomposition, activated carbon adsorption, biological treatment, or the like. The applied treatment method should be selected according to the power installation conditions, but it should also be possible to respond to changes in the components dissolved in the waste liquid and the degree of a by adjusting the pressure, changing the type and quantity of ultrafiltration membranes, etc. Reverse osmosis treatment is preferred.

It is preferable to use an ultrafiltration membrane having a molecular weight cut-off of 5,000 to 10,000 in the development waste solution and stripping waste solution recovery system according to the present invention. Once dissolved, the photoresist component is a polymeric substance with a molecular weight greater than this molecular weight cutoff, so almost all of the photoresist component is transferred to the concentrated solution, and the alkaline agent and antifoaming solution remain in the permeate solution. It is.

The concentration ratio by this ultrafiltration membrane varies depending on the economic efficiency caused by the permeation rate, etc., but is suitably 10 to 20 times.

Next, a demonstration test using an embodiment of the processing method of the great invention will be described, but the present invention is not limited by this.

[Example] Using a polysulfone-based ultrafiltration membrane with a molecular weight cut-off of 10,000, a recycling test was carried out by subjecting development waste to ultrafiltration at an operating pressure of 20 kg/cm' and a temperature of 20 to 30°C. As a result, the amount of photorebst film dissolved was almost constant. The removal rate of dissolved organic matter by the ultrafiltration membrane was approximately 80%. 6. The smaller the pore size of the ultrafiltration membrane, the greater the separation performance.
00, the removal rate was 85%.

The 15 to 20% organic matter contained in the permeate from the ultrafiltration was the antifoaming agent contained in the original developer, and this was also able to be recovered. Permeated liquid from developer waste is approximately 95%
can be recovered up to.

Through this ultrafiltration, the volume of the developing waste liquid can be reduced to 1/10 to 1/20 of the liquid volume used in the printed circuit board manufacturing process.
a It can be discharged as a glue solution. next.

This concentrated solution was acidified with sulfuric acid to adjust the pH to 2-4. This allows most of the resist components (90 to 95
%) can be insolubilized. This insolubilized component is removed by dehydration filtration, and the acid-treated filtrate is subjected to reverse osmosis treatment to produce a glue solution that has shrunk by about 5 times and a C○D of less than about 20 mg/l, which has removed about 99% of the dissolved resist components. Excludes as permeate. After neutralization, this permeate was of such a level that it could be discharged or recovered as water for use.

[Effects of invention The present invention provides a method for treating waste liquid from manufacturing printed circuit boards.

This is a waste liquid treatment in which the developing solution or stripping solution is recycled using ultrafiltration. First, polymer substances such as dissolved photoresist are removed from the developing waste solution and stripping waste solution in the pretreatment process, and the a-condensed solution is removed. Second, organic matter can be removed by waste liquid treatment such as addition of acid, secondly, the development waste liquid and stripping waste liquid can be pre-treated to permeate and recover only the water and effective substances, and thirdly, they can be recycled. Technical effects such as a significant reduction in the total amount of photoresist dissolution waste liquid that must be treated and a significant reduction in waste liquid processing costs were obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a system for treating developing waste liquid or stripping waste liquid in printed circuit board manufacturing according to the present invention. FIG. 2 is a flow sheet showing a conventional waste liquid treatment system for manufacturing printed circuit boards. FIG. 3 is a flow sheet showing another example of a system for treating waste liquid from conventional printed circuit board manufacturing. FIG. 4 is a graph showing the ultrafiltration desert removal performance. Gofu7◆10210ko 2 57104 2
57+05 2nd Edition Nominal Fishing Surface Molecular Landscape Figure 4 Hand h''d Ne City 1F 3rd December 1985 Patent Office Officer Black 1) Ming Wei Dian 1, Incident Indication Patent Application No. 1988 171894 No. 2
, Title of the invention Photoresist waste liquid treatment method 3, Person making the amendment/Relationship with the matter Patent applicant address 2-2-1 Otemachi, Chiyoda-ku, Tokyo Name (2)
10) r, 4￥KMyV&6 type company gouda
Shigeru Representatives 1) Shigeru 4, Agent, Sumitomo Heavy Industries, Ltd., 2-2-1 Otemachi, Chiyo F-ku, Tokyo (7490) Patent Attorney Masanobu Kato (1 other person) 5, Sub-Agent Person Address: 11-16, Ichiban-cho, Chiyoda-ku, Tokyo 102, Subject of amendment Section 7 of [Detailed Description of the Invention] and [Brief Description of Drawings] of the specification, Contents of amendment (1) Page 2 of the specification In the first line, “Detection of [waste liquid]
Correct. (2) Insert ``Process `` after ``printed circuit board manufacturing'' in the second line of page 3 of the specification.
For example, ``inorganic materials of metal oxides 2 synthetic polymeric materials 1, for example, zirconium dioxide-based'' is corrected. (4) “Permeate liquid” on page 11, line 5 of the specification and line 8 of the same page is corrected to “permeate liquid”. (5) 1. Method of the present invention on page 11, line 12 of the specification Then, insert [Add NaOH until the pH of the processing solution (developing solution or stripping solution) is reached before dissolving the resist] after ``Y''. (6) Page 11, line 12 and 15 of the specification. Insert the following sentence between the lines: [Accumulation of Na ions can be prevented in the following way, i.e. in the processing solution: NatCOj+ HmO-NaHCO3+ Hydrolyzes like NaOH, and R the photoresist. When expressed as -OH, it dissolves as follows: Mascot + H + O → NaHCO + + Na
OHNaOH+ R-OH-R-OH+ HmO As this reaction progresses and consumes NaOH. HCO+- becomes constant, and the dissolving ability of the treatment liquid gradually decreases. The treated liquid whose dissolution ability has decreased to an unacceptable level is subjected to ultrafiltration as waste liquid, but the permeated liquid contains almost no Lenst components and only most of the inorganic alkaline components. Add NaOH to the permeate that has been processed through ultrafiltration at the pH value before dissolving the resist (in Table 1, pH = 11.5).
When the reaction is added until it reaches , an equilibrium reaction proceeds in the direction of the arrow in the first-order equation. Mascot + Lo'-NaHCO+ + N
a0)l↑ That is, as NaOH increases, the tP equilibrium moves to the left. co,'- ions increase, and a new group of processing liquids can be restored. Furthermore, an amount of fresh processing liquid is replenished in an amount corresponding to the amount of concentrated liquid that has been a-condensed by ultrafiltration and is discharged from the recovery system. This makes it possible to regenerate, recycle, and use the processing liquid waste (developing waste, stripping waste) without accumulation of Na ions or fluctuations in liquid volume. ] (7) On page 12, line 19 of the specification, 1 and photoresist are corrected to [ta)odresist]. (8) The following statement is inserted between line 8 and line 9 of page 13 of the specification. ([Example 1] Based on the recycling treatment system for developing waste solution and stripping waste solution shown in Figure 1, developer solution (pH 11.5, resist not dissolved)
was repeated 15 times in a batch operation. Regarding the processing of the developer according to the present invention, the liquid quality of the developer waste, the ultrafiltration membrane permeate, and the regenerated developer in each cycle is shown in the graph of FIG. The membrane used was a polysulfone flat membrane manufactured by Millipore (fraction molecule 'Ic 10000, membrane area 0.012 m1), and the ultra-uJ membrane was operated at an operating pressure of 3 kg/am'. The operation was carried out at a liquid temperature of 20"C and a reduction ratio of 20 times. Component adjustment was carried out by adding NaOH to the permeate of 950 ml/Torr obtained from 1000 ml/Torr of a sample developing waste solution (pH 10.5) to a pH of 11.5. After adding 50 milliliters of newly prepared developer solution (equivalent to the amount of condensed liquid), the developer solution was repeatedly regenerated and the experiment was conducted.As a result, p
After adjusting to H11.5, it was confirmed that the NaeI degree of the regenerated developer was constant. It is observed that the resist component CTOC (total organic carbon content) accumulates in the permeate of ultrafiltration as the number of repetitions progresses, but this cannot be concentrated infinitely, however, 5% new It was found that because the developer was being replenished, equilibrium was reached at a concentration commensurate with the dilution rate. 1. with new developer. The viscosity, which was OcP, increased to 1.8 cP after the resist was dissolved. It was found that the regeneration process according to the method of the present invention also had a regeneration effect on the viscosity of the developer. The printed circuit board was developed by spraying a developer at a constant temperature and pressure for several tens of seconds. In order to prevent insufficient development due to a decrease in spray flow rate, etc., it was necessary to suppress the -F increase in liquid viscosity. ) (9) "Example 2" on page 13, line 9 of the specification is corrected to "Example 2." (10) "Brief explanation of the drawings" section in Ming-Old, i.e., page 15. The first row from the bottom shows the TOC of the developer waste solution and membrane permeation regeneration solution when the developer is repeatedly regenerated.
and is a graph showing the degree of NaLy')a of the regenerated developer. Insert ko. (11) Figure 5 of the attached drawings is supplemented as shown in the attached sheet.

Claims (1)

[Claims] A method for treating waste development liquid or waste stripping liquid discharged from a printed circuit board manufacturing process, wherein the waste development liquid or waste peeling liquid containing photoresist is separately subjected to ultrafiltration, and the waste liquid is passed through the ultrafiltration membrane. A photoresist waste liquid treatment method characterized by repeatedly reusing the solution as a developing solution or a stripping solution, respectively.