JP2003218072A - Waste water treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste water treatment apparatus that extends the replacement period by a large amount for a filter used for treating discharged drain in a process for manufacturing semiconductors, and can substantially reduce the maintenance work. <P>SOLUTION: The waste water treating apparatus has a polishing means for supplying demineralized water to a polishing section and at the same time, for polishing a semiconductor, a filtering means having a circulation tank for storing and circulating drain discharged from the polishing section, a filter for filtering grinding fine particles from the drain to obtain permeated water, and a circulating apparatus that transports the drain in the circulation tank to the filter and makes concentrated water to flow back to the circulation tank, and a reflux means for making the permeated water flow back to the polishing means. In this case, a disinfection or strerilization means is provided between the polishing section and the circulation tank. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating wastewater discharged from a semiconductor polishing apparatus, and in particular to treating wastewater for the purpose of suppressing problems such as filter clogging due to the action of fungi contained in the wastewater. Regarding the device.

[0002]

2. Description of the Related Art A large amount of waste water containing wafer grinding / polishing powder is discharged from a semiconductor assembling process such as a semiconductor assembling process such as dicing (wafer chip division) and back grinding (back surface polishing). Has been done.

Since ultrapure water used in such dicing and back grinding processes is very expensive, it is desirable to separate it from waste water and reuse it. Also, when treating wastewater as industrial waste, it is preferable to separate and collect and reuse the wastewater from the viewpoint of shortening the wastewater treatment time and reducing the amount of waste.

Therefore, in recent years, the above waste water is separated into filtered water and concentrated water containing grinding fine particles by a filter or the like, and the separated filtered water is regenerated into ultrapure water to be reused in the dicing or back grinding process. ing.

[0005]

However, about 10 ² to 10 ³ bacteria / ml of bacteria are contained in polishing waste water discharged from the semiconductor manufacturing process such as back grinder and dicing saw used for polishing and cutting wafers. Are present, and in some cases, these fungi grow in the processor and
It becomes about ⁵ pieces / ml, which may be 10% or more of the SS concentration (Suspended Solid suspended solids).

If such bacteria or bacteria adhere to the filter, they cannot be easily removed even by an operation such as backwashing, and the filter should be removed once every 2-3 days. It had to be replaced, which took a lot of effort, time and money.

The present invention has been made in order to solve the above problems, and it prolongs the replacement period of the filter used for the treatment of the wastewater discharged in the semiconductor manufacturing process, and greatly increases the maintenance work. It is an object of the present invention to provide a wastewater treatment device that can reduce the amount of wastewater.

[0008]

A waste water treatment apparatus of the present invention comprises a polishing means for polishing a semiconductor while supplying pure water to the polishing portion, and a circulation for storing and circulating the waste water discharged from the polishing portion. A tank, a filter for filtering ground fine particles from the waste water to obtain permeated water, and a filtering means having a circulating device for transporting the waste water in the tank to the filter and returning concentrated water to the tank again, In a wastewater treatment device comprising a reflux means for refluxing the permeated water to the polishing means, a sterilizing or sterilizing means is arranged between the polishing section and the tank.

Further, another waste water treatment apparatus of the present invention comprises a polishing means for polishing the semiconductor while supplying pure water to the polishing section,
A circulation tank for storing and circulating the wastewater discharged from the polishing section, a filter for filtering permeated particles from the wastewater to obtain permeate, and a concentrated water for transporting the wastewater in the tank to this filter. In a wastewater treatment device comprising a filtering means having a circulation device for returning the water to the tank again and a reflux means for returning the permeated water to the polishing means, a sterilizing or sterilizing means is provided in a part of the filtering means. It is characterized by being set up.

In the above wastewater treatment equipment, further, an ion exchange means for removing an ionic component from the permeated water is provided between the filtration means and the reflux means for refluxing the permeated water from the filtration means to the polishing section. Preferably.

The sterilization or sterilization means may be, for example, a method in which a bactericidal agent is added, or a physical method such as heating, ultraviolet irradiation or ultrasonic irradiation.

Such a wastewater treatment apparatus of the present invention is preferably used for treating polishing wastewater discharged when polishing a GaAs semiconductor.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing an example of the wastewater treatment equipment of the present invention. The new pure water is sent to the polishing section 2 of the polishing means 1 such as a back-grinding device, and becomes waste water in which grinding fine particles are mixed. The wastewater discharged from the polishing section 2 is
Before filtering, wastewater is sterilized / sterilized by a sterilization / sterilization means. This sterilization / sterilization is performed by, for example, the sterilization / sterilization tank 3, the sterilization / sterilization means, and the like.

Examples of the sterilization / sterilization means include a chemical sterilizer 4a and a physical sterilizer 4b. Examples of the chemical sterilizer 4a include a device to which sodium hypochlorite, hydrogen peroxide solution, ozone, etc. are added individually or in combination. Examples of the physical sterilization device 4b include heating,
Examples thereof include ultraviolet irradiation and ultrasonic irradiation.

When performing sterilization treatment using sodium hypochlorite, for example, a predetermined amount of waste water is sterilized / sterilized in the tank 3
Then, it is sterilized by adding it to a hypochlorous concentration of 5 to 20 mg / l.

The chemical sterilizer 4a and the physical sterilizer 4b may be used in combination, or only one of them may be used. The sterilization / sterilization may be performed continuously or intermittently.

By thus sterilizing and sterilizing the wastewater in advance before flowing the wastewater into the filtering means, contamination of live bacteria with the filtering means is suppressed, and the filter used for the filtration is the It is possible to suppress clogging due to the increasing action.

Next, the sterilized and sterilized wastewater is sent to the filtration means 5 for filtration. The filtering means 5 includes a circulation tank 6 for storing and circulating waste water, a filter 7 for separating the waste water into permeated water and concentrated water, and a pump 8 for circulating the waste water between the circulation tank 6 and the filter 7. And a circulation device. The filter 7 used for filtering the waste water is, for example, a microfiltration membrane or an ultrafiltration membrane, and its pore size is preferably about 0.05 to 0.2 μm.

A sterilizing / sterilizing means is provided in a part of the filtering means 5, and the wastewater is circulated to separate permeated water and concentrated water, and at the same time, sterilizing / sterilizing treatment is performed.

Examples of the sterilizing / sterilizing means include a chemical sterilizing device 4a and a physical sterilizing device 4b. For example, FIG.
As shown in FIG.
The sterilizing agent may be added to the circulation tank 6 adjacent to, or a part of the circulation path of the concentrated water may be branched, and a physical sterilization device 4b may be provided at this branched portion to pass therethrough. The concentrated water may be subjected to sterilization treatment such as heat treatment, ultraviolet ray irradiation, or ultrasonic wave irradiation.

The location for disposing such a sterilizer is not particularly limited. For example, these sterilizers may be arranged in the filter 7 portion or in the pipe connecting the circulation tank 6 and the filter 7, Any chemical or physical sterilization may be performed at least at any place.

Examples of the chemical sterilization device 4a include a device to which sodium hypochlorite, hydrogen peroxide solution, ozone, etc. are added. Examples of the physical sterilization device 4b include devices that perform heating, ultraviolet irradiation, and ultrasonic irradiation.

The chemical sterilizer 4a and the physical sterilizer 4b may be used in combination, or only one of them may be used. The sterilization / sterilization may be performed continuously or intermittently in the concentrated water circulation.

By disposing the sterilization / sterilization means in a part of the filtration means 5, it becomes possible to suppress the growth of microorganisms during the filtration and the clogging of the filter 7.

The filter 7 of the filtering means 5 is preferably provided with a backwashing means including a backwashing chamber 9 and an air injection section 10 for sending air to the backwashing chamber 9 in order to eliminate clogging.

The permeated water obtained by the filtering means 5 is once sent to and stored in the filtered water tank 11, and thereafter, various ions are removed by the ion exchange means 12. Examples of the ion exchange means 12 include a single anion / cation exchange resin and a mixed bed type, and a deionization device such as RO or EDI. The permeated water thus obtained can be used by being returned to the polishing means 1 again. On the other hand, the concentrated water remaining in the filtering means 5 is once stored and then discarded.

In the above-mentioned present invention, an example is shown in which the wastewater is sterilized once before being sent to the filtering means, and further sterilized during the filtration. However, both sterilization treatments are not necessarily required. Even if only one of them is sterilized, the effect is obtained.

[0029]

EFFECTS OF THE INVENTION According to the wastewater treatment equipment of the present invention, by sterilizing the wastewater before or during the filtration treatment of the wastewater discharged when polishing the semiconductor, the growth of bacteria inside the filtration equipment is carried out. It is possible to suppress the above, to significantly extend the filter replacement period, and to facilitate maintenance.

In particular, by using it for wastewater treatment when polishing a GaAs semiconductor in which bacteria easily grow, it is possible to suppress the growth of bacteria, significantly extend the filter replacement cycle, and facilitate maintenance. Become.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a wastewater treatment device of the present invention.

[Explanation of symbols]

1 ... Polishing means 2 ... Polishing part 4a ... Chemical and physical disinfection device 4b ... Physical sterilizer 5 ... Filtering means 6 ... Circulation tank 7 ... Filter 12 ... Ion exchange means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/36 C02F 1/42 A 4D064 1/42 1/44 E 1/44 1/50 510A 1/50 510 520J 520 531M 531 531Q 531R 540B 540 550C 550 550H 560A 560 560C 560E 1/72 Z 1/72 1/76 A 1/76 1/78 1/78 9 502 502E 502E 502E 503 504B 504 504E B01D 35/02 A H01L 21/301 H01L 21/78 Z F Term (Reference) 4D006 GA06 GA07 KA31 KA33 KB03 KB04 KD06 MA22 MB02 PA01 PB07 PB22 PB23 PC06 4D025 AA06 BA08 BA13 DA08 DA06 4A06 DA06 4 AA08 AB03 BA18 BA26 CA03 CA11 CA1 2 CA16 4D050 AA08 AB06 BB02 BB06 BB09 BD03 BD06 CA01 CA07 CA09 CA12 4D064 AA31 BA21 BA34

Claims (6)

[Claims] 1. A polishing unit for polishing a semiconductor while supplying pure water to the polishing unit, a circulation tank for storing and circulating the wastewater discharged from the polishing unit, and filtering fine grinding particles from the wastewater. A filter for obtaining permeated water, a filtering means having a circulator for transporting waste water in the circulation tank to the filter and returning concentrated water to the circulation tank again, and the permeated water is returned to the polishing means. A wastewater treatment device provided with a reflux means, wherein a sterilization or sterilization means is provided between the polishing section and the circulation tank. 2. A polishing means for polishing a semiconductor while supplying pure water to the polishing section, a circulation tank for storing and circulating the wastewater discharged from the polishing section, and filtering grinding fine particles from the wastewater. A filter for obtaining permeated water, a filtering means having a circulator for transporting waste water in the circulation tank to the filter and returning concentrated water to the circulation tank again, and the permeated water is returned to the polishing means. A wastewater treatment device provided with a reflux means, wherein a sterilizing or sterilizing means is provided in a part of the filtering means. 3. An ion exchange means for removing an ionic component from the permeated water is provided between the filtration means and a reflux means for returning permeated water from the filtration means to the polishing section. The wastewater treatment device according to claim 1 or 2, which is characterized. 4. The waste water treatment apparatus according to claim 1, wherein the sterilizing or sterilizing means is one that adds a sterilizing agent. 5. The sterilization or sterilization means is at least one selected from heating, ultraviolet irradiation and ultrasonic irradiation.
4. The method according to claim 1, wherein
The wastewater treatment device according to any one of 1. 6. The wastewater treatment equipment according to claim 1, wherein the semiconductor is a GaAs semiconductor.