JP4743388B2 - Disposal method of waste water containing photoresist - Google Patents

Description

  The present invention relates to a method for treating wastewater containing photoresist, such as cleaning wastewater for a substrate in a photolithography method.

  In the manufacturing process of integrated circuits (IC, LSI, etc.), printed circuit boards, color filters, liquid crystal displays, etc., as a development process, a photosensitive resin called photoresist is used as a substrate such as a wafer, glass plate, copper clad laminate, etc. For example, the photoresist is exposed to light through a photomask on which a development pattern is formed and photoreacted, and an exposed portion or an unexposed portion of the photoresist is removed with a developer such as an alkaline aqueous solution to form a predetermined pattern. After forming the film, a photolithography method for cleaning the substrate is used. In this photolithography method, the drainage generated during the cleaning of the substrate contains a photoresist.

  An example of a method for treating the photoresist-containing wastewater thus produced is a filtration method. In this filtration method, the photoresist-containing wastewater is usually filtered under alkaline conditions, but under such conditions, the photoresist is difficult to aggregate, and it is difficult to perform stable operation because it is difficult to aggregate suitable for a filtration membrane. There is a problem that there is.

In addition, as a method for treating photoresist-containing wastewater, the substrate cleaning wastewater (containing tetraalkylammonium and a small amount of photoresist) in the photolithography method is supplied under pressure to the reverse osmosis membrane device under pH 5 or more and less than 9 conditions. A method to do this has been proposed (Patent Document 1).
JP 2001-276824 A

  However, in the above method, tetraalkylammonium can be treated effectively to some extent, but it has not yet been satisfactory in terms of the aggregate filterability and operational stability of the photoresist in the treatment with a filter membrane.

  In view of such a situation, an object of the present invention is to provide a method for treating a photoresist-containing wastewater that can treat the photoresist-containing wastewater with good agglomeration filterability and operational stability.

In order to achieve the above object, the photoresist-containing wastewater treatment method of the present invention adjusts the pH of the photoresist-containing wastewater to 5 or less , which is acidic , and then adjusts the pH of the photoresist-containing wastewater after the pH adjustment to the acidity. It is characterized in that the pH is adjusted to 8-9 which is alkaline, and the pH is adjusted to 6.5-7.5 so as to be suitable for the coagulation and precipitation of the photoresist to coagulate and precipitate the photoresist, and the film treatment is performed. (Claim 1).

According to the above invention (Invention 1), the photoresist contained in the wastewater is modified (insolubilized) by adjusting the pH of the photoresist-containing wastewater to acidic, and then the pH of the wastewater is further reduced by the aggregate precipitation of the photoresist. By adjusting so as to be suitable for the above, the aggregation filterability of the photoresist can be improved, and thus the film treatment can be performed stably. Furthermore, according to the said invention (invention 1), when the object substrate of photolithography is a copper clad laminated board etc., even when copper is contained in the photoresist containing wastewater by etching etc., the photoresist containing wastewater Since copper inside can be deposited, copper can be removed from waste water.

  According to the present invention, it is possible to treat a photoresist-containing wastewater with good aggregation filterability and operational stability.

Hereinafter, one embodiment of the processing method of the photoresist content drainage concerning the present invention is described.
FIG. 1 is a flowchart illustrating a method for treating photoresist-containing wastewater according to an embodiment of the present invention.

  In the method for treating resist-containing wastewater according to the present embodiment, wastewater generated at the time of washing the substrate in the development process during the manufacturing process of integrated circuits (IC, LSI, etc.), printed boards, color filters, liquid crystal displays, etc. Thus, waste water containing a photosensitive resin called a photoresist is treated water (raw water).

  In the photoresist-containing wastewater treatment method according to this embodiment, first, the pH of the raw water is adjusted to be acidic (S1). Examples of the photoresist contained in the raw water include a positive photoresist such as a mixture of a phenol resin and a quinonediazide, and a negative photoresist such as a cyclized rubber-bisazide. The raw water usually exhibits alkalinity by containing an aqueous alkali solution as a developer, and the photoresist is generally alkali-soluble. Therefore, by adjusting the pH of the wastewater to acidic, the photoresist is in the wastewater. It can precipitate and become insoluble. In this treatment, the pH of the raw water is preferably adjusted to 5 or less, particularly preferably 3 to 4.

  The method of adjusting the pH of the raw water to be acidic is not particularly limited, and can be performed, for example, by adding a pH adjuster. Any pH adjuster may be used as long as it can adjust the pH of the photoresist-containing wastewater to acidic, and examples thereof include citric acid, hydrochloric acid, sulfuric acid, lactic acid, acetic acid, and salts thereof. The addition amount of the pH adjusting agent can be appropriately changed according to the type of the pH adjusting agent, but is preferably an amount capable of adjusting the pH of the raw water exhibiting alkalinity to 5 or less.

Next, when copper is contained in the photoresist-containing wastewater, for example, when the target substrate of photolithography is a copper clad laminate, the pH of the wastewater adjusted to acidity as described above is made alkaline. Adjust (S2). Thus, by adjusting the pH of the wastewater to be alkaline, copper (Cu) contained in the wastewater can be precipitated as copper hydroxide (Cu (OH) ₂ ). In this treatment, the pH of the wastewater is preferably adjusted to 8-9, and particularly preferably adjusted to 8.5-9.

  The method for adjusting the pH of the photoresist-containing wastewater to be alkaline is not particularly limited, and can be carried out, for example, by adding a pH adjuster. The pH adjuster is not particularly limited as long as the pH of the photoresist-containing wastewater can be adjusted to be alkaline, and examples thereof include sodium hydroxide, aqueous ammonia, sodium carbonate and the like. The addition amount of the pH adjusting agent can be appropriately changed according to the type of the pH adjusting agent, but is preferably an amount capable of adjusting the pH of the resist-containing waste water to 8-9.

  In addition, when copper is not contained in the photoresist-containing wastewater or when it is extremely small even if copper is contained and it is not necessary to separate the wastewater from the wastewater, the treatment (S2) for adjusting the wastewater to be alkaline is performed. It may be omitted.

  Subsequently, the pH of the waste water is adjusted to a pH suitable for the aggregation and precipitation of the photoresist (S3). By this treatment, the state of aggregation of the photoresist in the subsequent aggregation precipitation treatment can be improved. In this treatment, the pH of the waste water is preferably adjusted to a neutral region, specifically 6.5 to 7.5.

  The method of adjusting the pH of the photoresist-containing wastewater to a pH suitable for coagulation precipitation as described above is not particularly limited, and can be performed, for example, by adding a pH adjuster. As the pH adjuster, the same pH adjuster as used when adjusting the pH of the raw water to be acidic can be used. The addition amount of the pH adjusting agent can be appropriately changed according to the type of the pH adjusting agent, but may be an amount capable of adjusting the pH of the photoresist-containing waste water to 6.5 to 7.5. preferable.

  A flocculant is added to the photoresist-containing wastewater adjusted to a pH suitable for aggregation precipitation as described above, and the photoresist is aggregated and precipitated (S4). The photoresist deposited and insolubilized in the above-described acidification treatment (S1) has high adhesiveness, but by adding a flocculant and coagulating and precipitating the photoresist, the subsequent film treatment is stabilized. Can be done. In addition, the copper hydroxide precipitated by the alkalinization treatment (S2) can be precipitated by this treatment.

  The flocculant is not particularly limited as long as it can coagulate and precipitate the photoresist in the waste water. For example, polyaluminum chloride (PAC), sulfuric acid band, ferric chloride, polymer flocculant, and the like can be used. it can. The amount of the flocculant added is not limited as long as the photoresist can be sufficiently coagulated and settled. Can be changed.

  Finally, the waste water subjected to the above treatment is introduced into the membrane separation device, and membrane treatment is performed (S5). By this film treatment, treated water from which the photoresist and copper hydroxide have been removed can be obtained. Membrane treatment can be performed by a conventional method, and for example, can be performed under pressure using a membrane separation apparatus equipped with a separation membrane such as a microfiltration membrane, an ultrafiltration membrane, and a reverse osmosis membrane.

  According to the method for treating photoresist-containing wastewater according to the present embodiment, the photoresist contained in the wastewater can be modified and coagulated, so that wastewater film treatment can be performed efficiently. Moreover, even if it is a case where copper is contained in waste_water | drain, copper can be efficiently removed with a photoresist.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, the coagulation sedimentation treatment (S4) and the membrane treatment (S5) in the present embodiment may be performed substantially simultaneously.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to the following Example at all.

[Aggregation test]
Photoresist-containing wastewater (pH; 10.9, TOC; 8.3 ppm, Fe; 38.2 ppm, Cu; 1.35 ppm) 1 L of hydrochloric acid as a pH adjusting agent was added to adjust the pH of the photoresist-containing wastewater to 3. The resist contained in the waste water was deposited by adjusting to 0. Next, caustic soda as a pH adjuster was added to adjust the pH of the wastewater to 9.0, and copper contained in the wastewater was precipitated as copper hydroxide. Thereafter, hydrochloric acid as a pH adjuster was added to adjust the pH of the wastewater to 7.0, and PAC was added as a flocculant to coagulate and precipitate the photoresist in the wastewater.

  The drainage of the aggregated and precipitated photoresist and copper hydroxide is filtered using 5A filter paper (manufactured by Advantech), and then filtered using a Millipore filter (pore size: 0.45 μm, manufactured by Nippon Millipore). The filtration time and the filtration time using a filter (filtration start to 500 mL filtration time: T1,500 mL filtration time to 1000 mL filtration time: T2) were measured. Moreover, the Micro Filter Function (MFF) value (T2 / T1) was calculated from the filtration time by the filter.

As a comparative example, except that the step of adjusting the pH of the photoresist-containing wastewater to 3.0 is omitted, a pH adjuster is added in the same manner as in the examples, the coagulation treatment is performed, the filtration time with the filter paper, and the filtration with the filter The time was measured, and the MFF value was calculated from the filtration time through the filter.
The results of the above test are shown in Table 1.

  As shown in Table 1, in the examples, the aggregated state of the photoresist was good, so that the filtration time with the filter paper and the filtration time with the filter were shorter than in the comparative example, and stable membrane treatment could be performed. Moreover, in the Example, MFF value was less than 1.1 and it was confirmed that the filtration performance is excellent.

[Water flow test]
About the photoresist containing waste water of the said Example and a comparative example, it membrane-processes using 5A filter paper and a Millipore filter similarly to the said agglomeration test, About the permeated water amount 3 hours after the membrane treatment start and the membrane treatment start. A water flow test was conducted by measuring and calculating the permeated water amount down rate (%).
The results of the above test are shown in Table 2.

  As shown in Table 2, in the comparative example, the permeated water amount down rate was 13% after 3 hours from the start of the membrane treatment, whereas in the examples, the permeated water amount even after 3 hours from the start of the membrane treatment. There was no change. From this, it was confirmed that according to the processing method of the photoresist containing waste water concerning this example, an effective film processing can be performed.

  INDUSTRIAL APPLICABILITY The present invention is useful for the treatment of waste water (cleaning waste water) generated at the time of cleaning a substrate in a development process in the manufacturing process of an integrated circuit (IC, LSI, etc.), a printed board, a color filter, a liquid crystal display and the like.

It is a flowchart which shows the processing method of the photoresist containing waste_water | drain which concerns on one Embodiment of this invention.

Claims (1)

After adjusting the pH of the photoresist-containing wastewater to 5 or less which is acidic, the pH of the photoresist-containing wastewater after adjusting the pH to the acidity is adjusted to 8 to 9 which is alkaline, and further for coagulating precipitation of the photoresist. A method for treating photoresist-containing wastewater, wherein the pH is adjusted to 6.5 to 7.5 so as to be suitable, the photoresist is coagulated and precipitated, and film treatment is performed.

Images