WO2004096717A2 - Method and apparatus for treating waste water - Google Patents

Method and apparatus for treating waste water Download PDF

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Publication number
WO2004096717A2
WO2004096717A2 PCT/JP2004/006167 JP2004006167W WO2004096717A2 WO 2004096717 A2 WO2004096717 A2 WO 2004096717A2 JP 2004006167 W JP2004006167 W JP 2004006167W WO 2004096717 A2 WO2004096717 A2 WO 2004096717A2
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Prior art keywords
waste water
copper
treatment
treating waste
water
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PCT/JP2004/006167
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English (en)
French (fr)
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WO2004096717A3 (en
Inventor
Sota Nakagawa
Masaji Akahori
Makoto Kashiwagi
Keiji Maishigi
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Ebara Corp
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Ebara Corp
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Priority to US10/554,462 priority Critical patent/US20060243604A1/en
Priority to JP2006507724A priority patent/JP2006527067A/ja
Publication of WO2004096717A2 publication Critical patent/WO2004096717A2/en
Publication of WO2004096717A3 publication Critical patent/WO2004096717A3/en
Anticipated expiration legal-status Critical
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C02F1/4676—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electroreduction
    • C02F1/4678—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electroreduction of metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B15/00—Obtaining copper
    • C22B15/0063—Hydrometallurgy
    • C22B15/0084—Treating solutions
    • C22B15/0086—Treating solutions by physical methods
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
    • C25C1/12—Electrolytic production, recovery or refining of metals by electrolysis of solutions of copper
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D21/00—Processes for servicing or operating cells for electrolytic coating
    • C25D21/16—Regeneration of process solutions
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/469—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis
    • C02F1/4693—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis
    • C02F1/4695—Treatment of water, waste water, or sewage by electrochemical methods by electrochemical separation, e.g. by electro-osmosis, electrodialysis, electrophoresis electrodialysis electrodeionisation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56—Macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/70—Treatment of water, waste water, or sewage by reduction
    • C02F1/705—Reduction by metals
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46152—Electrodes characterised by the shape or form
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
    • C02F2103/346—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from semiconductor processing, e.g. waste water from polishing of wafers
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4612—Controlling or monitoring
    • C02F2201/46125—Electrical variables
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a method and apparatus for removing and recovering metal such as copper from various kinds of waste water to be treated.
  • waste water containing heavy metal such as waste water produced in plating, waste water produced in semiconductor device fabrication processes, waste water produced in fabrication of printed circuit boards, or waste water produced in mines, it has been required to remove heavy metal from waste water and recover the heavy metal as needed.
  • 25A thorough 25E show an example of a process for forming an interconnection on a semiconductor substrate.
  • a conductive layer 202 is formed on a semiconductor substrate 201 on which semiconductor devices have been formed, and an insulating film 203 of Si0 2 is deposited on the conductive layer 202.
  • a contact hole 204 and an interconnection groove 205 are formed in the insulating film 203 by lithography etching technology.
  • a barrier layer 206 is formed on the insulating film 203.
  • the barrier layer 206 is made of metal such as Ta, TaN, TiN, WN, SiTiN, CoWP, or CoWB, or metallic compound thereof.
  • a copper seed layer 207 which is used as a feeding layer in electrolytic plating, is further formed on the barrier layer 206 by sputtering or the like .
  • a catalyst layer 207 is formed on the barrier layer 206 by pretreatment instead of the copper seed layer.
  • electrolytic copper plating or electroless copper plating is applied onto a surface of the copper seed layer 207 or the catalyst layer 207 to fill the contact hole 204 and the interconnection groove 205 with copper and to deposit a copper layer 208 on the insulating film 203.
  • the copper layer 208 on the insulating film 203 is removed by chemical mechanical polishing (CMP) or electrochemical polishing (ECP) so that a surface of the copper layer 208 filled in the contact hole 204 and the interconnection groove 205 is substantially flushed with a surface of the insulating film 203.
  • CMP chemical mechanical polishing
  • ECP electrochemical polishing
  • Waste water containing a large number of copper ions is produced in an electrolytic copper plating process and an electroless copper plating process in a semiconductor device fabrication process, and a chemical mechanical polishing (CMP) process and an electrochemical polishing (ECP) process for microchips having integrated circuits.
  • CMP chemical mechanical polishing
  • ECP electrochemical polishing
  • a maximum concentration of copper ions is restricted to 3.0 mg/1 or lower in Japan.
  • a concentration of copper ions is more strictly limited than in Japan.
  • a maximum concentration of copper ions is restricted to 2.7 mg/1 or lower
  • an average concentration of copper ions per day is restricted to 1.0 mg/1 or lower
  • an average concentration of copper ions per year is restricted to 0.4 mg/1 or lower.
  • a single CMP apparatus produces waste water having a maximum flow rate of about 0.5 m 3 /h and having a maximum copper concentration of about 100 mg/1.
  • a single copper plating apparatus produces waste water having a maximum flow rate of about 0.2 m 3 /h and having a maximum copper concentration of about 100 mg/1.
  • the total flow rate of waste water containing copper becomes as high as about 220 m 3 /day at the maximum, and the total amount of copper contained in the waste water becomes as much as about 22 kg-Cu/day at the maximum.
  • waste water has been treated by a comprehensive waste water treating system in which waste water has been collected from various processes in a plant and has been collectively treated.
  • a semiconductor device fabrication industry in which fabrication processes have been rapidly improved, there has been required to treat waste water discharged from respective processes on the point of use, i.e., at locations where water has been used. This reason is as follows: Production systems have changed from conventional mass production into diversified flexible production. Types of products are changed so frequently that variation of properties of waste water becomes numerous.
  • CMP chemical mechanical polishing
  • the present inventors have found from an extensive study that as a method for treating waste water containing copper discharged from a semiconductor device fabrication process, copper in waste water can be efficiently removed and recovered by combining electrolytic deposition operation and electrodialysis operation. Specifically, according to one aspect of the present invention, there is provided a treatment method for treating water containing copper by combining electrolytic deposition operation and electrodialysis operation.
  • a method for treating waste water containing copper comprising: treating waste water in a copper treatment step comprising a combination of electrodialysis operation and electrolytic deposition operation to produce treated water having a lowered copper concentration; and recovering copper from the waste water.
  • a method for treating waste water containing copper comprising: decomposing oxidizing agent in waste water in an oxidizing agent decomposition step; supplying the waste water discharged fromthe oxidizing agent decomposition step to a copper treatment step; treating the waste water in the copper treatment step comprising a combination of electrodialysis operation and electrolytic depositionoperationtoproduce treatedwaterhaving a lowered copper concentration; and recovering copper from the waste water.
  • an oxidizing agent such as hydrogen peroxide
  • a titania-supported platinum catalyst or an alumina-supported platinum catalyst catalytic decomposition with a manganese dioxide catalyst, electrolysis, ultraviolet-rays treatment, ozone addition, decomposition treatment with a reducing agent such as hydrazine, sodium thiosulfate or sodium sulfite, and enzymatic hydrolysis with an H 2 0 2 degrading enzyme (catalase) , etc.
  • a platinum catalyst such as an alumina-supported platinum catalyst, it is preferred to use a honeycomb-shaped catalyst because of its large specific surface area, its good gas-separability and increased decomposition rate.
  • a honeycomb-shaped catalyst can be provided with successive openings in the flow direction, so that particles smaller than the opening area may be passed through the openings without being accumulated in the catalyst .
  • the honeycomb-shaped catalyst can therefore be advantageously used for decomposing an oxidizing agent contained in slurry-containing waste water such as CMP waste water.
  • the oxidizing agent decomposition step may use a platinum-coated catalyst.
  • the oxidizing agent decomposition step may comprise a hydrogen peroxide decomposition step.
  • the copper recovered from the waste water may comprise copper metal .
  • a method for treating waste water may further comprise a slurry separation step for separating slurry from the waste water, the slurry separation step being providedbetween the oxidizing agent decomposition step and the copper treatment step.
  • the slurry separation step may include coagulating separation treatment or filtering treatment.
  • the copper treatment step may comprise a separation step for separating and concentrating copper in the waste water by electrodialysis operation as CuS0 concentrated water, a recovering step for depositing copper on a cathode of an electrolytic deposition apparatus by electrolytic deposition operation of the CUSO4 concentrated water, and an acid recovery step for recovering sulfuric acid from treated water of the recovery step.
  • amethod for treatingwastewater may further comprise a ⁇ potential converting step provided at a preceding stage of the copper treatment step; wherein the waste water containing solid fine particles may be treated by the ⁇ potential converting step.
  • the waste water containing solid fine particles may be directly introduced into the copper treatment step when a ⁇ potential of the fine particles is a negative value.
  • organic compound having sulfo group may be added to the waste water.
  • the solid fine particles may comprise abrasive particles used in a CMP step.
  • the abrasive particles may contain at least one of Si0 2 , A1 2 0 3 and Ce0 2 .
  • a surfactant or a pH adjusting agent may be added to the waste water.
  • a method for treating waste water containing copper comprising: treating waste water in a copper treatment step comprising a combination of electrodialysis operation and electrolytic depositionoperationtoproduce treatedwaterhaving a lowered copper concentration, the waste water comprising waste water discharged from a CMP step for polishing a semiconductor substrate having a copper layer thereon and/or a cleaning step for cleaning the polished semiconductor substrate using a cleaning liquid; and recovering copper from the waste water.
  • amethod for treatingwastewater may further comprise a ⁇ potential converting step provided at a preceding stage of the copper treatment step.
  • the surfactant may comprise an anionic surfactant or a nonionic surfactant.
  • the anionic surfactant may contain no metal cation.
  • the solid fine particles may comprise abrasive particles, and the abrasive particles contain at least one of Si0 2 , A1 2 0 3 and Ce0 2 .
  • the cleaning liquid in the cleaning step may contain a surfactant .
  • a method for treating waste water containing copper comprising: introducingwaste water into a ⁇ potential converting step to convert a ⁇ potential of solid fine particles in the waste water into a negative value, the waste water comprising waste water discharged from a CMP step for polishing a semiconductor substrate having a copper layer thereon and/or a cleaning step for cleaning the polished semiconductor substrate using a cleaning liquid; and treating the waste water containing the fine particles in an ion-exchange treatment step to produce treated water having a lowered copper concentration.
  • amethod for treatingwaste water may further comprise an oxidizing agent decomposition step provided at a preceding stage of the ion-exchange treatment step.
  • a method for treating waste water containing copper comprising: introducingwaste water into a ⁇ potential converting step to convert a ⁇ potential of solid fine particles in the waste water into a negative value, the waste water comprising waste water discharged from a CMP step for polishing a semiconductor substrate having a copper layer thereon and/or a cleaning step for cleaning the polished semiconductor substrate using a cleaning liquid; and treating the waste water containing the fine particles in a coagulating sedimentation treatment step or a coagulating separation treatment step to produce treated water having a lowered copper concentration.
  • amethod for treatingwastewater may further comprise an oxidizing agent decomposition step provided at a preceding stage of the coagulating sedimentation treatment step or the coagulating separation treatment step.
  • a method for treating waste water comprising: treating waste water discharged only from a copper polishing step in a CMP step to produce treated water having a lowered copper concentration.
  • the treating waste water may comprise at least one of electrodialysis treatment, electrolytic deposition treatment, ion-exchange treatment, and coagulating sedimentation treatment.
  • an apparatus for treatingwastewater containing copper comprising: an electrodialysis apparatus; and an electrolytic deposition apparatus; wherein waste water is treated by a combination of the electrodialysis apparatus and the electrolytic deposition apparatus to produce treated water having a lowered copper concentration and to recover copper.
  • the copper recovered from the waste water may comprise copper metal.
  • the electrodialysis apparatus may perform electrodialysis operation of the waste water to separate and concentrate copper in the waste water as CuS0 4 concentrated water; the electrolytic deposition apparatus may perform electrolytic deposition operation of the CuS0 4 concentrated water to deposit copper on a cathode of the electrolytic deposition apparatus; the apparatus for treating waste water may further comprise an acid recovery apparatus for recovering sulfuric acid from treated water discharged from the electrolytic deposition apparatus.
  • the electrodialysis apparatus mayhave a desalting chamber packed with an ion-exchanger.
  • an apparatus for treating waste water may further comprise a ⁇ potential converting apparatus provided at a preceding stage of the electrodialysis apparatus.
  • the ⁇ potential converting apparatus may comprise a chemical storage tank configured to store a surfactant or a pH adjusting agent, and an adding device configured to add the surfactant or the pH adjusting agent stored in the chemical storage tank to the waste water.
  • the surfactant may comprise an anionic surfactant or a nonionic surfactant.
  • FIG. 1 is a schematic view showing a treatment flow of a treatment method for treating waste water by combining electrolytic deposition operation and electrodialysis operation according to the present invention
  • FIG. 2 is a schematic view showing an overall treatment flow in which the treatment flow of FIG. 1 is shown in detail
  • FIG. 3 is a schematic view showing a hydrogen peroxide decomposition step in detail
  • FIG.4 is a schematic view showing a slurry separation step in detail
  • FIG. 5 is a schematic view showing an example of a copper treatment step
  • FIG. 6 is a schematic view showing another example of a copper treatment step
  • FIG. 7 is a schematic view showing an electrolytic deposition apparatus according to a first embodiment of the present invention
  • FIGS. 8A and 8B are schematic views showing electrolytic deposition apparatuses according to a second embodiment of the present invention.
  • FIG. 9 is a schematic view showing a method for treating hydrogen gas generated in electrolytic deposition apparatuses and electrodialysis apparatuses according to the present invention
  • FIG. 10 is a schematic view showing another method for treating hydrogen gas generated in electrolytic deposition apparatuses and electrodialysis apparatuses according to the present invention
  • FIG. 11 is a schematic view showing a method for treating hydrogen gas generated in electrolytic deposition apparatuses and electrodialysis apparatuses according to the present invention
  • FIGS. 12A and 12B are conceptual views showing a method of detecting an abnormal state by monitoring water in quality or in quantity which is obtained by a waste water treatment apparatus according to the present invention
  • FIG.13 is a schematic view showing a waste water treatment systemfor treating aste waterproduced in a semiconductor device fabrication process
  • FIG.14 is a schematic view showing a relationship between a CMP apparatus and a waste water treatment system according to the present invention
  • FIG. 15 is a schematic view showing a case of introducing waste water discharged from an apparatus that carries out etching and cleaning steps, or plating, etching and cleaning steps in the same chamber into a waste water treatment system;
  • FIG. 16 is a schematic view showing a case of collectively treating waste water discharged from a plurality of apparatuses that perform an identical step
  • FIG.17 is aperspective view showing awastewater treatment unit provided within a casing
  • FIGS. 18A and 18B are views showing preferable positional relationships between a CMP apparatus, a plating apparatus or an ECP apparatus and a waste water treatment system according to the present invention
  • FIGS. 19A through 19C are views showing cases of collectively treating waste water discharged from apparatuses that perform different process steps
  • FIG.20 is a schematic view showing a waste water treating system according to an embodiment of another aspect of the present invention
  • FIGS. 21A and 21B are schematic views showing a method of installing, in a semiconductor device fabrication plant, a waste water treatment apparatus according to an embodiment of the present invention
  • FIG. 22 is a schematic view showing a copper treatment apparatus according to an embodiment of another aspect of the present invention
  • FIGS. 23A and 23B are schematic views showing treatment flows in a case where a ⁇ potential converting step is provided upstream of a copper treatment step;
  • FIGS .24A and 24B are schematic views showing a ⁇ potential converting apparatus for carrying out the ⁇ potential converting step
  • FIGS .25Athrough 25E are schematic views showing an example of a process for forming a copper interconnection in a semiconductor chip
  • FIG. 26 is a schematic view showing an electrodialysis apparatus for performing two steps between a set of an anode and a cathode
  • FIG.27 is a schematic view showing an example of a membrane combined-type electrolytic deposition apparatus
  • FIGS.28A and 28B are schematic views showing examples of Cu-CMP apparatuses.
  • FIG. 1 is a schematic view showing a treatment flow of a treatment method for treating waste water by combining electrolytic deposition operation and electrodialysis operation according to the present invention.
  • Waste water (water to be treated) containing copper and discharged from a Cu-CMP step or a Cu plating step 1 in a semiconductor device fabrication process is supplied to a hydrogenperoxide decomposition step 2.
  • hydrogen peroxide contained in the waste water is decomposed by a platinum-coated catalyst.
  • the waste water discharge from the hydrogen peroxide decomposition step 2 is supplied to a slurry separation step 3.
  • a slurry containing abrasive particles which comprise silica or alumina is used, andhence the slurry is aggregatedand separated in the slurry separation step 3.
  • a supernatant liquid of the slurry separation step 3 is supplied to a copper treatment step (Cu treatment step) 10 to recover Cu (copper) in the form of copper metal.
  • the copper treatment step 10 comprises three steps of a separation step 11, a recovery step 12 and an acid recovery step 13.
  • the waste water discharged from the slurry separation step 3 is subj ected to electrodialysis operation in an electrodialysis apparatus provided in the separation step 11, thereby separating and concentrating Cu in the waste water as CuS0 4 concentrated water.
  • the CuS0 4 concentrated water is supplied to the recovery step 12, and is subjected to electrolytic deposition in an electrolytic deposition apparatus provided in the recovery step 12, thereby depositing Cu on the cathode.
  • Treated water of the recovery step 12 is supplied to the acid recovery step 13, and sulfuric acid is recovered by an acid recovery apparatus provided in the acid recovery step 13.
  • the recovery of sulfuric acid means that S0 4 2 ⁇ whichhas moved froma H 2 S0 4 circulation line to a CuS0 4 concentrated water circulation line in the separation step 11 is returned to the H 2 S0 4 circulation line by the electrodialysis operation. This recovery allows a concentration of sulfuric acid in the H 2 S0 4 circulation line to be maintained.
  • the separation step and the acid recovery step may be provided adjacent to each other or may be integrated with each other.
  • an electrodialysis apparatus for performing both steps between a set of an anode and a cathode may be constructed.
  • two electrolytic deposition apparatuses are arranged in parallel in the recovery step 12.
  • One of the electrolyticdeposition apparatuses is shownbyreferencenumeral 20A and the other is shown by reference numeral 2OB.
  • the electrolytic deposition apparatus 20B is separated from the circulation system. While the electrolytic deposition apparatus 20A performs electrolytic deposition operation on Cu in the CuS0 concentrated water, the electrolytic deposition apparatus 2OB serves to lower a Cu concentration in the remaining CuS0 concentrated water in the tank. After the Cu concentration in the tank is lowered sufficiently, water in the tank is discharged. After water is discharged from the tank, the tank is filledwith acid solution usingpure water and sulfuric acidnewly.
  • the CuS0 4 concentratedwater circulation line is switched from the electrolytic deposition apparatus 20A to the electrolytic deposition apparatus 20B, and the CuS0 4 concentrated water is circulated through the electrolytic deposition apparatus 20B.
  • the electrolytic deposition apparatus 20 is separated from the circulation system andthe electrolytic depositionapparatus 20Bperforms deposition of Cu on the liquid remaining in the tank.
  • the discharge ' place may be the same as the discharge place of the treated water, or may be different from the discharge place of the treated water. If there is a limit to an installation space of the apparatus or the concentration of cations other than copper is extremely low, two electrolytic deposition apparatuses are not be necessarily required in parallel, and a single electrolytic deposition apparatus may be sufficient.
  • a treated water tank 14 serves to store treated water which has been treated to remove Cu in the separation step 11. Needless to say, the pH adjustment can be made in accordance with circumstances of the discharge place of the treated water.
  • the slurry separation step 3 is put in parentheses, and this means that water discharged from the hydrogen peroxide decomposition step 2 may be directly supplied to the copper treatment step 10 without providing the slurry separation step 3. If the slurry separation step is provided, then part of Cu in the waste water is discharged together with sludge generated by separation of slurry as mother liquid attached or adhered to the sludge, and hence such discharged Cu does not become an object to be treated in the copper treatment step. In a case where water containing slurry is supplied to the copper treatment step 10 as it is, all of Cu contained in the waste water can be supplied to the copper treatment step. Thus, the recovery rate of Cu can be substantially increased.
  • FIG. 2 is a schematic view showing an overall treatment flow in which the treatment flow of FIG. 1 is shown in detail.
  • a single electrolytic deposition apparatus is shown.
  • waste water discharged fromthe Cu-CMP step or the Cuplating step 1 is supplied to an adjustment tank 21, and is stirred by a stirrer 21a in the adjustment tank 21.
  • Decomposition of hydrogen peroxide is performed by using a platinum-coated catalyst comprising a metal honeycomb substrate and platinum coated by a surface of the metal honeycomb substrate in a hydrogen peroxide decomposition tower 22.
  • Three columns 22a, 22b and 22c packed with the platinum-coated catalyst are provided in the hydrogen peroxide decomposition tower 22, and waste water is passed through the three columns 22a, 22n and 22c in series, thereby decomposing hydrogen peroxide into oxygen gas and water.
  • a mixing tank 31 a coagulating tank 32, a solid-liquid separation tank 33, a circulation tank 34, a centrifugal separator 35, and a ceramic membrane 36.
  • Ferric chloride serving as inorganic coagulant and potassium hydroxide serving as alkali are added to form coagulated floes in the mixing tank 31.
  • Other known inorganic coagulant and alkali maybe used.
  • a polymer coagulant is added in the coagulating tank 32.
  • the polymer coagulant preferably comprises anionic polymer coagulant. Additive rate of the polymer coagulant is in the range of 1 to 5 mg/1, preferably 3 mg/1.
  • additive rate is in the range of 5 to 200 mg/1, preferably 50mg/l .
  • Potassium hydroxide is added as alkaline agent so that a pH of waste water becomes 5.
  • polymer coagulant By adding polymer coagulant, coagulated floes are enlarged to increase sedimentation velocity of the coagulated floes.
  • the obtained sedimentation velocity is different from each other depending on additive rate of polymer coagulant, andis, however, approximately 100mm/minute depending on the properties of slurry.
  • solid matter concentrate of coagulated floe
  • liquid are separated from each other.
  • the sludge settled and separated in the solid-liquid separation tank 33 is supplied to the centrifugal separator 35, and dehydrated sludge whose water content is about 85% can be obtained.
  • Mother liquidcontainingCuandrecoveredinthe centrifugal separator 35 is circulated and returned to the mixing tank 31.
  • Supernatant liquid obtained in the solid-liquid separation tank 33 is filtered by the ceramic membrane 36 to become permeated water because coagulated floes or particles are removed almost completely.
  • the hole diameter of the ceramic membrane 36 is in the range of 0.1 to 1.0 ⁇ m, preferably 0.1 ⁇ m.
  • the obtained flux is inthe range of about 0.5 to 2m 3 / (m 2 day) .
  • Theoperatingpressure is in the range of 5 to 20 m-H 2 0.
  • the permeated water is stored in a permeated water tank 37.
  • the water discharged from the permeated water tank 37 is supplied to the copper treatment step 10.
  • the recovery step 12 of the copper treatment step 10 may be performed by a single electrolytic deposition apparatus .
  • the single electrolytic deposition apparatus may be sufficient, if coexistent cation concentration is low or coexistent cation is allowed to continue to be concentrated in the CuS0 4 circulation line . It shouldbe noted that two ormore electrolytic deposition apparatuses may be provided in parallel and alternate operation of the electrolytic deposition apparatuses may be performed.
  • FIG. 3 is a schematic view showing a hydrogen peroxide decomposition step in detail.
  • an adjustment tank 21 andahydrogen peroxide decomposition tower 22 are provided in the hydrogen peroxide decomposition step 2.
  • the adjustment tank 21 temporarily stores waste water discharged from the Cu-CMP step or the Cu plating step 1 and the adjustment tank 21 serves to suppress variation in water quality and supply the waste water with uniform composition to a subsequent stage.
  • the adjustment tank 21 may be supplied with acid or alkali as a pH adjusting agent.
  • the pH adjustment means that the pH is adjusted to at least 6 or less, preferably 5 or less by adding acid to waste water, in consideration of the fact that copper exists as copper hydroxide, i.e., a solid object in a case where the waste water itself discharged from the Cu-CMP step or the Cu plating step 1 has a high value of pH, so that even copper which is present in a state of copper hydroxide changes into a state of Cu 2+ ions. Changing the state of copper into Cu 2+ ions enables the performance of the copper treatment step 10 at the subsequent stage to be kept efficient.
  • a hydrogen peroxide decomposition tower 22 in the hydrogen peroxide decomposition step 2 comprises three columns 22a, 22b and 22c packed with a platinum-coated metal honeycomb catalyst.
  • the amount of platinum coated by the metal honeycomb catalyst is in the range of 1 to 10 g/1, preferably in the range of 2 to 5 g/1.
  • Cell density density (density of honeycomb pores) is in the range of 100 to 1000 cell/square inch, preferably in the range of 200 to 600 cell/square inch.
  • the metal honeycomb catalyst preferably comprises a substrate to which acid resistant coating is applied.
  • LV linear velocity
  • the contact time is in the range of 1 to 10 minutes, preferably in the range of 3 to 5 minutes.
  • Oxygen gas generated by decomposing hydrogen peroxide into oxygen and water is discharged from the hydrogen peroxide decomposition tower 22 through gas-liquid separation apparatuses 23. After decomposition of hydrogen peroxide, treated water is supplied to the slurry separation step 3, or is directly supplied to the copper treatment step 10 without being passed through the slurry separation step 3.
  • the number of columns in the hydrogen peroxide decomposition tower 22 may be less than 3 if the amount of hydrogen peroxide to be decomposed is small. If the amount of hydrogen peroxide to be decomposed is large, the amount of oxygen gas generated by decomposition of hydrogen peroxide increases, and substantial residence time of water becomes short. Therefore, the number of columns may be three or more for the purpose of separating oxygen gas from the water to be treated.
  • FIG.4 is a schematic view showing a slurry separation step in detail.
  • a mixing tank 41 a coagulating tank 42, a solid-liquid separation tank 43, a circulation tank 44, a permeated water tank 37 and a ceramic membrane 45.
  • Treated water which has been treated in the hydrogen peroxide decomposition step is supplied to the mixing tank 41.
  • FeCl 3 is supplied as inorganic coagulant.
  • a pH of liquid in the mixing tank 41 becomes about 2.7.
  • the treated water is adjusted to a pH of about 5 by supplying alkali. With this adjustment, fine floes of iron hydroxide are produced. Water discharged from the mixing tank
  • apolymer coagulant for example, 0.1% solution as raw liquid
  • apolymer coagulant for example, 0.1% solution as raw liquid
  • the solid-liquid separation tank 43 is arranged such that the velocity of upward flowofwater is equal toor smaller than the sedimentationvelocity of sludge.
  • the supernatant liquid is supplied to the ceramic membrane 45, and permeated water is stored in the permeated water tank 37.
  • the ceramic membrane is operated such that while water is circulated, part of water is obtained as permeated water which has passed through the membrane, and the flow rate of water which is ten times that of permeated water is circulated.
  • Material of membrane may be organic polymer other than ceramics.
  • the centrifugal separator 35 used in the slurry separation step comprises a decanter-type centrifugal separator, and concentrated sludge obtained in the solid-liquid separation tank 43 is further concentrated and dehydrated by the centrifugal separator.
  • the centrfigal separator having an acceleration of about 3000 to 5000 G may be used.
  • FIGS. 5 and 6 are schematic views showing an example of a copper treatment step.
  • the copper treatment step 10 shown in FIG.5 comprises three steps of a Cu separation step 51, a Cu recovery step 52 and an acid recovery step 53, for example.
  • the Cu separation step 51 serves to separate and recover Cu in raw water as CuS0 4 concentrated water by electrodialysis operation.
  • the electrodialysis apparatus for performing the Cu separation step has five chambers of a first desalting chamber 54, a second desalting chamber 55, a concentrating chamber 56, a cathode chamber 57 and an anode chamber 58.
  • raw water is supplied to the first desalting chamber 54.
  • the first desaltingchamber 54 is packedwith cation-exchange nonwoven fabric produced by graft polymerization. Further, the first desalting chamber 54 and the adjacent chamber are partitioned by a cation-exchange membrane.
  • Cu in the raw water is captured by the cation-exchange nonwoven fabric, and the captured Cu moves to the concentrating chamber 56 by a potential gradient between a positive electrode and a negative electrode. Cations other than Cu contained in the raw water behave like Cu.
  • Water discharged from the first desalting chamber 54 is temporarily stored in an intermediate tank 59, and water discharged from the intermediate tank 59 is supplied to the second desalting chamber 55.
  • the intermediate tank is not necessarily provided. If the intermediate tank is not provided, the water discharged from the first desalting chamber 54 is directly supplied to the second desalting chamber 55.
  • the second desalting chamber 55 is packed with cation-exchange nonwoven fabric produced by cation-exchange graft polymerization in the same manner as the first desalting chamber 54. With this arrangement, Cu leaking out from the first desalting chamber (intermediate desalting chamber) 54 is also captured and removed in the second desalting chamber 55, and the captured Cu can be finally moved through the first desalting chamber 54 to the concentrating chamber 56 by apotential gradient.
  • the second desalting chamber 55 and the adjacent chamber are partitioned by a cation-exchange membrane.
  • Water discharged fromthe seconddesalting chamber 55 becomes treatedwater finally.
  • a gas such as air may be added to inflow water of the first and second desalting chambers 54, 55.
  • the strong fluidity generated by adding the gas has an effect of removing the captured slurry fromthe cation-exchange nonwoven fabric.
  • Cu ions supplied from the first desalting chamber 54 and the second desalting chamber 55 are mixed with S0 4 2 ⁇ supplied from sulfuric acid filled in the cathode chamber 57 to produce CuS0 4 concentrated water, and the produced CuS0 concentrated water is supplied to the Cu recovery step 52.
  • current condition is as follows: Constant current operation is performed and current density is set in the range of 1 to 4 A (ampere) /dm 2 , preferably about 3A/dm 2 . In this case, voltage is in the range of 10 to 40 V.
  • the thicknesses of the desalting chamber and the concentrating chamber are in the range of 3 to 10 mm, preferably in the range of 3 to 5 mm.
  • the sulfuric acid is added so that the CuS0 concentrated water is adjusted to a pH of not more than 2, preferably not more than 1.5.
  • the CuS0 4 concentrated water has a copper concentration of 500 to 3000 ppm, preferably about 1000 ppm. If the copper concentration is not more than 500 ppm, a Cu deposition rate in the Cu recovery step is low, and hence an area of the electrode required for deposition becomes large, resulting in a large-sized apparatus. If the copper concentration is not less than 3000 ppm, the difference of copper concentration between the concentrating chamber and the first desalting chamber in the Cu separation step becomes too large, resulting in a lowering of efficiency due to generation of back-diffusion.
  • the copper concentration of the CuS0 concentrated water may be lower than the copper concentration of the raw water.
  • the pH in the H 2 S0 circulation line is. not more than 2.0, preferably not more than 1.5.
  • the pH adjustment of liquid in the CuS0 concentrated water circulation line or the H 2 S0 circulation line is performedby adjusting current value supplied to the electrodialysis apparatus for carrying out the acid recovery step or by adding sulfuric acid.
  • the Cu recovery step 52 copper is recovered as Cu metal on a surface of the cathode by electrolytic deposition operation.
  • two or more electrolytic deposition apparatuses may be provided in parallel, and alternate operation of the electrolytic deposition apparatuses may be performed.
  • a single electrolytic deposition apparatus may be provided.
  • the acid recovery step 53 serves to return S0 2+ ions concentrated in the CuS0 concentrated water circulation line by electrodialysis operation to the H 2 S0 circulation line.
  • the chamber to which CuS0 4 concentrated water is supplied and the chamber to which sulfuric acid aqueous solution is supplied are separated from each other by an anion-exchange membrane, and S0 4 2_ is moved from the CuS0 concentrated water to the sulfuric acid aqueous solutionby applying apotential between thepositive electrode and the negative electrode.
  • S0 4 2 ⁇ concentration in the CuS0 concentrated water circulation line and the H 2 S0 4 circulation line can be a steady concentration.
  • the thickness of each chamber except for an electrode chamber is in the range of 3 to 10 mm, preferably 3 to 5 mm.
  • the current density in the acid recovery apparatus provided in the acid recovery step 53 is 2 to 3 A/dm 2 .
  • a plurality of acid recovery apparatuses are required depending on the ability of the acid recovery step 53.
  • apluralityof acid recovery apparatuses having the same structure may be arranged in parallel .
  • a bipolar type apparatus may be used to increase a processing ability per one apparatus.
  • a copper treatment step shown in FIG. 6 is different from the copper treatment step shown in FIG. 5 in that a cell in the Cu separation step 51 has a chamber between the concentrating chamber 56 and the cathode chamber 57 for allowing sulfuric acid aqueous solution to circulate therethrough, and the cathode chamber 57 is packed with pure water.
  • This structure allows OH " generated in the cathode chamber 57 to flow directly into the concentrating chamber 56, so that the phenomena of depositing of Cu(OH) 2 in the concentrating chamber 56 can be suppressed. Further, it is possible to suppress a demerit that pressure is applied to a circulating path of liquid or ion-exchange function is impaired because an ion exchanger and an ion exchange membrane are covered with Cu(OH) 2 .
  • pure water may be continuously supplied to the electrode chamber or circulated through the electrode chamber.
  • a filtering facility comprising a filter for filtering outflow water of the Cu recovery step may be provided to remove fine powder of Cu metal produced in the Cu deposition step.
  • a bipolar type apparatus may be provided in the same manner as the acid recovery step 53.
  • FIGS. 7, 8A and 8B are schematic views showing an electrolytic deposition apparatuses.
  • FIG. 7 shows an electrolyticdepositionapparatus accordingto a first embodiment of the present invention
  • FIG. 8A and 8B show electrolytic deposition apparatuses according to a second embodiment of the present invention.
  • the reference numeral 61 represents a reference electrode such as a calomel electrode
  • the reference numeral 62 represents an electrolytic deposition bath
  • the reference numeral 63 represents a stirrer
  • the reference numeral 64 represents a power supply unit.
  • the cathode potential is measured by the reference electrode, and current value is adjusted so that the cathode potential is kept constant at a predetermined value. In this case, generation of OH " and a lowering of current efficiency caused by electrolysis of water can be suppressed.
  • the cathode potential should be set to -0.3 to 0.2 (V), preferably -0.1 to 0.1 (V) .
  • FIG.8A and 8B are schematic views showing the electrolytic deposition apparatuses 70A and 70B according to a second embodiment of the present invention.
  • Both of electrolytic deposition apparatuses 70A and 70B shown in FIGS. 8A and 8B comprise a cartridge-type apparatus, and the cartridge is replaced entirely after closing the upper and lower valves 71, andhence the cathode onwhich Cu is deposited sufficiently can be replacedwithout exposing the Cumetal . With this arrangement, the replacement work can be easily carried out.
  • the electrolytic deposition apparatus 70A has a single cathode 72.
  • the electrolytic deposition apparatus 70B has a plurality of cathodes 72 for the purpose of prolonging a service life of the cartridge. It is desirable for both of the anode 73 and the cathode 72 to have water-permeability and gas-permeability.
  • the cathode 72 foamed metal or net-like electrode or lath plate-like electrode may be used.
  • the anode 73 the same structure or the same material may be employed. Aplurality of cartridges ma be provided in a single system, and may be arranged in series or in parallel.
  • the electrolytic deposition apparatuses 70A and 7OB may comprise a cartridge-type apparatus as shown in FIGS. 8A and 8B. However, the electrolytic deposition apparatus may comprise other-type apparatuses, and the known-type apparatuses may be employed.
  • the electrolytic deposition apparatus may use a method for scraping copper deposited on the surface of the cathode by a scraper, and recovering the copper into a bag filter.
  • the electrolytic deposition apparatus comprises a membrane combined-type electrolytic deposition apparatus, as shown in FIG. 27, which has a water tank 171 in which a cathode 175 is provided, a water tank 172 in which an anode 176 is provided, and an ion-exchange membrane 173 which separates the water tank 171 and the water tank 172, then the CuS0 4 concentrated water is supplied only to the water tank 171 in which the cathode 175 is provided.
  • a fibrous material comprising polymer fibers as substrates to which ion-exchange groups are introducedby graft polymerization.
  • the substrates of polymer fibers to be grafted may either be single fibers of a polyolefine such as polyethylene or polypropylene, or composite fibers comprising a core portion and a sheath portion in which the core portion and the sheath portion are made of different polymers respectively.
  • Example of composite fibers which can be used in the present invention is composite fibers having a core-sheath structure in which a polyolefin such as polyethylene constitutes the sheath and other polymer such as polypropylene which is not used for the sheath constitutes the core.
  • the ion-exchange fibrous materials which are obtainedby introducing ion-exchange groups into the composite fibers by a radiation-induced graft polymerization, are excellent in the ion-exchange ability and can be produced with a uniform thickness, and therefore are desirable as ion-exchange fibrous materials to be used for the above object.
  • the ion-exchange fibrous material may be in the form of a woven fabric, nonwoven fabric, and the like.
  • an ion exchanger in the form a spacer member such as a diagonal net an ion exchanger comprising a polyolefin resin is preferably used for its excellent ion exchange ability and excellent ability to disperse the water to be treated.
  • a polyethylene diagonal net which is widely employed in electrodialysis baths is used as substrates and ion-exchange ability is imparted by utilizing a radiation-induced graft polymerization, then desirable ion exchanger is obtained.
  • the radiation-induced graft polymerization is a technique for introducing a monomer into polymer substrates by irradiating the polymer with radiation rays so as to produce a radical which reacts with the monomer.
  • Radiation rays usable for the radiation-induced graft polymerization include ⁇ -rays, ⁇ -rays, ⁇ -rays, electronbeam, ultraviolet rays, and the like. Of these, ⁇ -rays or electron beam may preferably be used in the present invention.
  • the radiation-induced graft polymerization there are a pre-irradiation graft polymerization comprising previously irradiating graft substrates with radiation rays and then contacting the substrates with a grafting monomer, and a co-irradiation method in which irradiation of radiation rays is carried out in the co-presence of substrates and a grafting monomer. Both of these methods may be employed in the present invention.
  • polymerization methods such as a liquid-phase graft polymerization method in which polymerization is effected while substrates are immersed in a monomer solution, a gas-phase graft polymerization method in which polymerization is effected while substrates are in contact with vapor of monomer, and an immersion gas-phase graft polymerization method in which substrates are firstly immersed in a monomer solution and then taken out of the monomer solution and a polymerization is effected in a gas phase. Either method of polymerization may be employed in the present invention.
  • the ion-exchange groups to be introduced into fibrous substrates such as a nonwoven fabric, or into spacer substrates are not particularly limited.
  • Various kinds of cation-exchange groups and anion-exchange groups can be used.
  • usable cation-exchange groups include strongly acidic cation-exchange groups such as sulfo group, moderately acidic cation-exchange groups such as phosphoric group, and weakly acidic cation-exchange groups such as carboxy group.
  • Usable anion-exchange groups includeweaklybasic anion-exchange groups such as primary, secondary and tertially amino groups, and strongly basic anion-exchange groups such as quaternary ammonium group. Further, .
  • an ion exchanger having both of the above-described cation and anion groups may also be employed. Furthermore, it is also possible to use an ion exchanger having functional groups such as functional groups derived from iminodiacetic acid or its sodium salt, functional groups derived fromvarious amino acids includingphenylalanine, lysine, leucine, valine, proline or their sodium salts or functional groups derived from iminodiethanol .
  • ion-exchange groups can be introduced into fibrous substrates or spacer substrates by subjecting a monomer having such an ion-exchange group to graft polymerization, preferably radiation-induced graft polymerization, or by subjecting a polymerizable monomer having a group that are changeable into an ion-exchange group, to graft polymerization, followedby conversion of that group into the ion-exchange group.
  • Monomers having an ion-exchange group usable for this purpose may include acrylic acid (AAc) , methacrylic acid, sodium styrenesulfonate (SSS) , sodium methallylsulfonate, sodium allylsulfonate, sodium vinylsulfonate, vinylbenzyl trimethylammonium chloride (VBTAC) , diethylaminoethyl methacrylate, and dimethylaminopropylacrylamide.
  • acrylic acid AAc
  • SSS sodium styrenesulfonate
  • VTAC vinylbenzyl trimethylammonium chloride
  • BTAC vinylbenzyl trimethylammonium chloride
  • Sulfo group as a strongly acidic cation-exchange group may be introduced directly into substrates by carrying out radiation-induced graft polymerization in which sodium styrenesulfonate is used as a monomer.
  • Quaternary ammonium group as a strongly basic anion-exchange group may be introduced directly into substrates by carrying out radiation-induced graft polymerization in which vinylbenzyl trimethylammonium chloride is used as a monomer.
  • the monomer having groups that can be converted into ion-exchange groups may include acrylonitrile, acrolein, vinylpyridine, styrene, chloromethylstyrene, and glycidyl methacrylate (GMA) .
  • Sulfo group as a strongly acidic cation-exchange group may be introduced into substrates in such a manner that glycidyl methacrylate is introduced into the substrates by radiation-induced graft polymerization, and then react with a sulfonating agent such as sodium sulfite.
  • Quaternary ammonium group as a stronglybasic anion-exchange group may be introduced into substrates in such a manner that chloromethylstyrene is graft-polymerized onto substrates and then the substrates are immersed into an aqueous solution of trimethylamine to effect quaternary-ammonification.
  • sodium iminodiacetate group as a functional group can be introduced into substrates in such a manner that chloromethylstyrene is graft-polymerized onto substrates and the substrates react with a sulfide to make a sulfonium salt, and then the sulfonium salt reacts with sodium iminodiacetate.
  • sodium iminodiacetate as a functional group may be introduced into substrates in such a manner that chloromethylstyrene is graft-polymerized onto substrates and chloro group is substituted with iodine group and iodine group reacts with an iminodiacetic acid diethyl ester to substitute iodine group with an iminodiacetic acid diethyl ester group, and finallythe ester group reacts with sodiumhydroxide to convert the ester group into sodium salt.
  • an ion-exchange fibrous material in the form of a nonwoven fabric or awoven fabric is particularlypreferable.
  • Afibrousmaterial such as a woven fabric or a nonwoven fabric, as compared to materials in the form of beads, a diagonal net, and the like has a remarkably larger surface area, and therefore a larger amount of ion exchange groups can be introduced thereinto.
  • resin beads in which ion-exchange groups are present in micropores or macropores within the beads all the ion-exchange groups are present on the surfaces of fibers in the case of an ion-exchange fibrous material.
  • FIGS .9 through 11 Amethod in which hydrogen gas is mixed with a gas containing an equimolar or more oxygen, and the mixed gas is passed through a catalyst-packed layer 101, which is capable of recombining the hydrogen gas and the oxygen gas to produce water, to cause catalytic reaction, thereby making the concentration of the remaining hydrogen gas less than 4 % by volume which is the explosion limit concentration (see FIG.
  • FIGS. 12A and 12B A ethod for monitoring the quality or quantity of treated water obtained by the above-described waste water treatment apparatus according to the present invention and detecting its abnormality will be described with reference to FIGS. 12A and 12B.
  • the reference numeral 105 denotes a waste water treatment apparatus according to any one of the above-describedembodiments of thepresent invention
  • 104 denotes water to be treated
  • 107 denotes treated water.
  • the concentration of copper ions of the treated water 107 obtained from the waste water treatment apparatus 105 according to the present invention is measured by means of a copper ion concentration measurement device 106.
  • the measurement device maybe designed such that it gives an alarmwhen the concentration of copper ions of the treated water becomes higher than a set value.
  • a shortage of electric current in the electrolytic deposition apparatus or the electrodialysis apparatus, an increase in the concentration of copper ions of the raw water, and deterioration of an ion exchanger due to electrodialysis treatment maybe consideredas the causes .
  • These maybe dealt withby a rise of operation current in the electrolytic deposition apparatus or electrodialysis apparatus, replacement of the ion exchanger, or the like.
  • Copper ion concentration measurement devices usable for this purpose may include measuring devices based on ion-selective electrode, electrode polarography, HPLC electrophoresis, fluorometry, etc.
  • the copper ion concentration measurement device 106 is provided in a line branched from the treated water line, the copper ion concentration measurement device 106 may be provided in the treated line.
  • the flow rate of treated water 107 obtained from the waste water treatment apparatus 105 according to the present invention may be measured with a flow indicator (FI) . When the amount of treated water becomes lower than a set value, the apparatus may give an alarm.
  • FI flow indicator
  • a polishing liquid for use in the CMP process can contain as an additive an oxidizing agent, such as hydrogen peroxide, iron nitrate, sodiumpersulfate or ammoniumpersulfate. Further, after forming a copper film on the surface of a wafer in a copper plating process, the copper film adhering to a peripheral portion
  • a so-called bevel-etching is carried out to remove the copper film adhering to the peripheral portion or the back surface of the wafer by dissolving the copper film with an acid, such as hydrochloric acid, sulfuric acid, citric acid or oxalic acid while oxidizing the copper film with an oxidizing agent such as hydrogen peroxide.
  • an acid such as hydrochloric acid, sulfuric acid, citric acid or oxalic acid
  • an oxidizing agent such as hydrogen peroxide.
  • Such an oxidizing agent particularly hydrogen peroxide
  • electrolysis of hydrogen peroxide progresses in preference to electrolytic deposition of a heavy metal such as copper. If a large amount of hydrogen peroxide is contained in waste water, a larger electric current is required for electrolytic deposition.
  • FIG.13 shows an embodiment of a treatment system for waste water from a semiconductor device fabrication processes in view of the above.
  • waste water from various processes 108 such as a CMP process, an ECP process, and a copper plating process, is first treated in an oxidizing agent removing step 109, and then treated in a waste water treatment apparatus 110 according to the present invention which employs electrolytic deposition operation and electrodialysis operation in combination.
  • the reference numeral 111 denotes treated water.
  • FIG. 14 shows a relationship between a CMP apparatus and awastewater treatment systemaccording to thepresent invention.
  • the CMP apparatus 112 includes a polishing unit (a polishing step) 112a and a cleaning unit (a cleaning step) 112b. In the polishing step 112a, a wafer is polished.
  • Liquids such as pure water and a chemical liquid (s) containing a slurry, adispersant, an acid, an alkali, a chelating agent, etc., are used in the polishing step 112a.
  • Waste water from such liquids is introduced into the waste water treatment system (the waste water treatment apparatus) 110.
  • the cleaning step 112b the slurry, abrasive particles and the chemical liquid remaining on the wafer are cleaned off with pure water, etc.
  • Such a cleaning waste water is also introduced into the waste water treatment system.
  • the polishing unit 112a may be one that performs electrochemical polishing. Substances peculiar to the waste water discharged from the polishing step 112a andthe cleaning step 112b is containedtherein.
  • the polishing step and the cleaning step are performed in multistage, respectively, in some cases. If the polishing step comprises a Cu polishing step and other steps such as a barrier-layer polishing step than the Cu polishing step, and most of discharged Cu is derived from the Cupolishing step, then ' it is desirable that waste water discharged only from the Cu polishing step is treated by the waste water treatment apparatus according to the present invention.
  • a chemical treatment 112c for example, separation of SS produced by edge-chipping, and dissolution or separation of a metal powder
  • the polishing step and the cleaning step are performed in multistage, respectively, in some cases. If the polishing step comprises a Cu polishing step and other steps such as a barrier-layer polishing step than the Cu polishing step, and most of discharged Cu is derived from the Cupolishing step, then ' it is desirable that waste water discharged only from the Cu polishing step is treated by the waste water treatment apparatus according to the present invention.
  • the polishing step comprises a Cu polishing step and other steps such as
  • waste water discharged only fromthe Cupolishingunit canbe treated.
  • the Cu-CMP apparatus shown in FIG.28B by switching the draining line of the polishing unit automatically depending on the type of the polishing step, waste water discharged only from the Cu polishing unit can be treated.
  • FIG.15 shows a case of introducing waste water discharged from an apparatus that carries out etching and cleaning steps, or plating, etching and cleaning steps in the same chamber into a waste water treatment system.
  • FIG. 15 an etching step and a cleaning step, or a plating step, an etching step and a cleaning step are performed in the same chamber 13a.
  • An electrochemical method such as electrochemical polishing, may be used in the etching step.
  • Chemical mechanical polishing (CMP) may also be used. It is possible to introduce all the waste water from the respective steps into the waste water treatment system (the waste water treatment apparatus 110) , or to introduce only the waste water from part of the steps into the waste water treatment apparatus 110.
  • FIG. 16 shows a case of collectively treating waste water discharged from a plurality of apparatuses that perform an identical step.
  • waste water from polishing apparatuses such as CMP apparatuses 112
  • waste water from a group of apparatuses thatperform a certain identical step for example, step A
  • waste water from another group of apparatuses that perform a different step for example, step B or step C
  • waste water from another group of apparatuses that perform a different step for example, step B or step C
  • FIG.17 is aperspective view showing awaste water treatment unit (a waste water.treatment system) provided within a casing.
  • FIG.17 shows a waste water treatment unit 113 that maybe provided with at least one of a pH adjustment device (pH adjustment unit) 113b, an internal negative pressure-forming device, a waste water-receiving tank, a caster for movement, and the like within a casing 114.
  • the internal negative pressure-forming device may be one that is controlled by pressure indicator signals.
  • the casing 114 may be a dividable one.
  • the waste water treatment unit 113 having the above structure can be installed in a space that requires a certain high level of cleanness, such as a clean room or its downstairs space.
  • FIGS. l ⁇ and 18B show preferable positional relationships between a CMP apparatus, an ECP apparatus or a plating apparatus and a waste water treatment system according to the present invention.
  • the reference numeral 115 denotes a clean room.
  • the waste water treatment apparatus 110 is installed right below a semiconductor manufacturing apparatus 116 (a plating apparatus 118 or a CMP apparatus 112) via a grating 117.
  • the waste water treatment apparatus 110 is installed adjacent to a semiconductor manufacturing apparatus 116.
  • the facility cost e.g. piping cost
  • the volume (size) of the entire factory can be made compact, thus reducing a construction cost of the entire factory.
  • FIGS.19A through 19C show cases of collectively treating waste water discharged from apparatuses that perform different process steps. For example, as shown in FIG. 19A, waste water discharged from an electrochemical polishing treatment step
  • 119b may be mixed and treated, in the waste water treatment system
  • waste water treatment apparatus 110 (the waste water treatment apparatus 110) .
  • waste water from apparatuses 120 that operate in the samemannerbutperformdifferent steps .(for example, CMP steps 120a, 120b) may be mixed and treated in the waste water treatment apparatus 110.
  • waste water with various natures discharged from a CMP process 121a and a plating step or a ECP step 121b into different treatment steps (for example, step 122 and step 123) of the waste water treatment system (the waste water treatment apparatus 110) .
  • Treated water may be withdrawn separately from different steps 122 and 123.
  • the waste water treatment apparatus may be arranged in two lines. By switching the lines upon exchange of replacement parts, such as an ion exchanger and a cathode of the electrolytic deposition apparatus, it becomes possible to secure a continuous treatment.
  • waste water from various processes 108 of semiconductor device fabrication processes is first received in a waste water tank 124, then subjected to the oxidizing agent removing step 109, and is then supplied to one of the two waste water treatment apparatuses 110 according to the present invention which employ electrolytic deposition operation and electrodialysis operation in combination, where copper ions are removed to obtain treated water 111.
  • the line is switched to allow the water to be treated to pass through the other waste water treatment apparatus 110, while exchange of the replacement parts of the apparatus, to which water supply is stopped, is made. A continuous treatment of the waste water is thus secured.
  • FIGS. 21A and 21B show installation methods of the waste water treatment system according to embodiments of the present invention in the case of using the waste water treatment system in an actual semiconductor device fabrication plant.
  • the reference numeral 130 denotes a semiconductor device fabricationplant
  • 131 denotes a copper plating apparatus
  • 132 denotes a polishing apparatus, such as a CMP or ECP apparatus
  • 133 denotes a waste water treatment apparatus or waste water treatment system according to any one of the above-described various embodiments of the present invention.
  • waste water from the copper plating apparatus 131 and the polishing apparatus 132 such as a CMP or ECP apparatus in the semiconductor device fabrication plant 130, is collected, and the collected waste water is treated by means of the waste water treatment apparatus or waste water treatment system 133 according to any one of the various embodiments of the present invention, whereby treated water 111, fromwhich copper ions such as copper have been removed, can be obtained.
  • the waste water treatment apparatus or waste water treatment system 133 according to any one of the various embodiments of the present invention, whereby treated water 111, fromwhich copper ions such as copper have been removed, can be obtained.
  • waste water from the copper plating apparatus 131 and waste water from the polishing apparatus 132 such as a CMP or ECP apparatus are collected separately, and the separately collected waste water is treated separately by means of the waste water treatment apparatus or waste water treatment system 133 according to any one of the various embodiments of the present invention, whereby treated water 111, from which heavy metal ions such as copper ions have been removed, can be obtained.
  • treatment of waste water can be carried out so as to meet the actual circumstances of apparatuses, in respective plants, which generate waste water by installing the waste water treatment apparatus of the present invention at the location where the waste water is generated.
  • the respective waste water from these apparatus may be treated either separately, or simultaneously as a mixture.
  • treated water 111 according to the present invention is discharged into a sewage line or supplied to a separate comprehensivewastewater treatment facility, an inappropriate water quality, such as pH, if any, should be adjusted in advance.
  • the ⁇ potential (zeta potential) of the surface (surface of electric double layer) of solid fine particles such as abrasive particles contained in the copper-containing waste water is either a negative value or a positive value .
  • the ⁇ potential of the surface of the solid fine particles is a negative value, no adverse effect on the Cu treatment step occurs .
  • the ⁇ potential of the surface of the solid fine particles is a positive value
  • the behavior of the solid fine particles is similar to that of Cu 2+ to cause the fine particles to be deposited on the surf ce of the cation-exchangemembrane inthe electrodialysis operation, or the fine particles are adsorbed together with Cu 2+ on a cation exchanger such as a cation exchange resin or a cation-exchange nonwoven fabric to cover adsorption sites in the ion exchange operation.
  • the waste water is pretreated to convert the ⁇ potential to a negative value, and is then supplied to the Cu treatment step.
  • a surfactant such as an anionic surfactant or a pH adjusting agent (acid or alkali) is added to the waste water.
  • the ⁇ potential value of the whole solid fine particles in the copper-containing waste water is influenced by the magnitude of the ⁇ potential of the individual solid fine particles and the existing rate of the solid fine particles, and shows either a positive value or a negative value.
  • the positive ⁇ potential value of the solid fine particles is converted to a negative ⁇ potential value by a ⁇ potential converting means to further lower the ⁇ potential value of the whole solid fine particles contained in the copper-containing waste water.
  • Types of surfactants may include anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.
  • anionic surfactants When the surfactant is used for converting the ⁇ potential fromapositivevalue to anegativevalue, it is desirable that an anionic surfactant in which the hydrophobic group part becomes anion.
  • anionic surfactants may include carboxylate salt-type surfactants, for example, fattyacid salts, ether carboxylate salts, alkenyl succinates, N-acylamino-acid salts, rhodinic acid salts (resinate) , or naphthenic acid salts; sulfuric ester salt-type surfactants, for example, primary alkylsulfuric ester salts, secondary alkylsulfuric ester salts, alkyl ether sulfuric ester salts, alkyl phenyl ether sulfuric ester salts, monoacylglycerine sulfuric ester salts, or sulfated oils/sulfated fatty acid alkyl esters; sulfonate-type surfactants, for example, ⁇ -olefin sulfonates, secondary alkyl sulfonates, ⁇ -sulfofatty acid ester salts, acyl isethionic acid salts, N-acyl
  • surfactants may include LIPOLAN PB-800 manufactured by Lion Corporation, POLITY N-100K manufactured by Lion Corporation, POLITY PS-1900 manufactured by Lion Corporation, POLITY A-550 manufactured by Lion Corporation, EMULGEN 1118 S-70 manufactured by Kao Corporation, and NEOPELEX manufactured by Kao Corporation.
  • an H-type surfactant in which a negatively chargedhydrophilic group is ionically bonded to a hydrogen ion is used.
  • An example of this type of surfactant is NEOPELEX GS which is manufactured by Kao Corporation and is an unneutralized product before the alkali hydrolysis step in the production process of a surfactant .
  • Additive rate of the surfactant varies depending upon properties of the solid fine particles such as a concentration of the solid fine particles and ⁇ potential of the solid fine particles. However, when the concentration of solid fine particles is in the range of 500 to 5000 mg/1 and the ⁇ potential of the whole solid fine particles in the copper-containing waste water is in the range of -50 mV to +50 mV, the additive rate of the surfactant is generally in the range of 10 to 1000 mg/1, preferably in the range of 10 to 500 mg/1.
  • the ⁇ potential after the addition of the surfactant is generally not more than -20 mV, preferably not more than -30 mV. However, this does not hold true for the case where a nonionic surfactant is used.
  • the molecular weight of the surfactant which can be used is in the range of 200 to 100000.
  • a surfactant having a relatively high molecular weight of not less than 10000 is used.
  • the surfactant as defined in the present invention is not particularly restricted by its name as far as the effect of dispersing the slurry or the effect of lowering the ⁇ potential can be obtained.
  • the surfactant includes materials called dispersants .
  • the surfactant includes organic materials having a sulfo group as a functional group.
  • the ⁇ potential can generally be lowered by increasing the pH with the addition of alkali.
  • Alkalis which can be used may include potassium hydroxide, sodium hydroxide, ammonia, and amine alkaline agents such as TMAH and choline.
  • a ⁇ potential converting step is provided at the preceding stage of the Cu treatment step.
  • the waste water is introduced directly into the Cu treatment step.
  • the ⁇ potential converting step may be provided at any position before the Cu treatment step. Specifically, the ⁇ potential converting step may be provided before or after the oxidizing agent decomposition step. The surfactant may be added at a position within the CMP apparatus.
  • the copper treatment step may be carried out by a combination of electrodialysis operation and electrolytic deposition operation, ion exchange treatment, coagulating sedimentation treatment, or the like.
  • waste water containing Cu and discharged from a CMP step and/or a cleaning step after the CMP step in a semiconductor device fabrication process is supplied to an oxidizing agent decomposition step 2A such as a hydrogen peroxide decomposition step.
  • an oxidizing agent decomposition step 2A such as a hydrogen peroxide decomposition step.
  • the oxidizing agent such as hydrogen peroxide or ammonium persulfate contained in the waste water is decomposed, for example, with a platinum-coated catalyst.
  • the waste water discharged fromthe oxidizing agent decomposition step 2A is supplied to a ⁇ potential converting step 5.
  • a surfactant such as an anionic surfactant or a pH adjusting agent is added to the waste water.
  • the ⁇ potential of fine particles contained in the waste water is converted to a negative value in the ⁇ potential converting step 5.
  • the waste water after this converting step is introduced into a copper treatment step 10, and treated in the copper treatment step 10.
  • treated water having a lowered copper concentration is obtained, and copper is recovered as a copper metal.
  • the oxidizing agent decomposition step 2A such as a hydrogen peroxide decomposition step and the Cu treatment step 10 are the same as those described in connection with the embodiments shown in FIGS. 1 through 8.
  • waste water containing Cu and discharged from a CMP step and/or a cleaning step after the CMP step in a semiconductor device fabrication process is supplied to a ⁇ potential converting step 5.
  • a surfactant such as an anionic surfactant or a pH adjusting agent is added to the waste water.
  • the ⁇ potential of fine particles contained in the waste water is convertedto anegativevalue inthe ⁇ potential converting step 5.
  • the waste water after this converting step is supplied to an oxidizing agent decomposition step 2A such as a hydrogen peroxide decomposition step.
  • the oxidizing agent such as hydrogen peroxide contained in thewastewater is decomposedby, for example, a platinum-coated catalyst .
  • the waste water discharged from the oxidizing agent decomposition step 2A is introduced into a copper treatment step 10, and treated in the copper treatment step 10.
  • treated water having a lowered copper concentration is obtained, and copper is recovered as a copper metal.
  • the oxidizing agent decomposition step 2A such as a hydrogen peroxide decomposition step and the copper treatment step 10 are the same as those described in connection with the embodiments shown in FIGS . 1 through 8.
  • FIGS. 24A and 24B are schematic views showing the construction of a ⁇ potential converting apparatus for carrying out the above-described ⁇ potential converting step.
  • the ⁇ potential converting apparatus comprises an stirring tank 150, a chemical liquid storage tank 151 for storing a chemical liquid such as a surfactant, and a pump 152 for supplying the chemical liquid stored in the chemical liquid storage tank 151 to the stirring tank 150.
  • the waste water containing copper and discharged from the CMP step and/or the cleaning step is supplied to the stirring tank 150.
  • the chemical liquid is supplied from the chemical liquid storage tank 151 to the stirring tank 150.
  • the ⁇ potential converting apparatus may be constructed such that the chemical liquid is supplied from the chemical liquid storage tank 151 directly to a waste water line 153 through the pump 152, and waste water containing copper and discharged from the CMP step and/or the cleaning step and the chemical liquid are mixed with each other in a line mixer 155 provided in the line 153.
  • the copper treatment step shown in FIGS. 23A and 23B may be performed by ion exchange treatment or coagulating sedimentation treatment which will be described below. Next, ion exchange treatment will be described below.
  • waste water which has been subjected to the ⁇ potential converting step or the oxidizing agent decomposition step is subjected to ion exchange treatment which uses an ion exchanger.
  • An ion exchanger comprises a column having bead-like ion exchange resin filled therein, a fabric material such as woven fabric or nonwoven fabric, a porous film, a spacer having diagonal meshes, or the like.
  • Waste water (water to be treated) containing metal ions is passed through a liquid filter apparatus having awater-permeable sheet formedbythe ion exchanger.
  • Metal ions M + in the waste water are adsorbed by the ion exchanger with ion exchange.
  • the metal ions M + contained in the waste water are removed and recovered more reliably.
  • the waste water may be passed through layers of the ion exchanger. Alternatively, the waste water may be passed along surfaces of layers of the ion exchanger.
  • any ion exchange resin beads known in the art may be used for this purpose.
  • strongly acidic cation-exchange resinbeads which are used in the present invention canbe obtained by using the beads as a basic resin comprising polystyrene which is crosslinked with divinylbenzene, and sulfonating the beads by a sulfonating agent such as sulfuric acid or chlorosulfonic acid to introduce sulfonic group into the basic resin.
  • a sulfonating agent such as sulfuric acid or chlorosulfonic acid
  • resinbeads which have various functional groups, for example, functional groups derived fromiminodiacetic acid and its sodium salt, functional groups derived from various amino acids such as phenylalanine, lysine, leucine, valine, proline and their sodium salts, and functional groups derived from iminodiethanol.
  • a fibrous material comprising polymer fibers as substrates to which ion-exchange groups are introduced by graft polymerization.
  • the substrates of polymer fibers to be grafted may either be single fibers of a polyolefine such as polyethylene or polypropylene, or composite fibers comprising a core portion and a sheath portion in which the core portion and the sheath portion are made of different polymers respectively.
  • Example of composite fibers which can be used in the present invention is composite fibers having a core-sheath structure in which a polyolefin such as polyethylene constitutes the sheath and other polymer such as polypropylene which is not used for the sheath constitutes the core.
  • the ion-exchange fibrousmaterials whichare obtainedbyintroducing ion-exchange groups into the composite fibers by a radiation-induced graft polymerization, are excellent in the ion-exchange ability and canbe producedwith auniformthickness, and therefore are desirable as ion-exchange fibrous materials to be used for the above object.
  • the ion-exchange fibrous material may be in the form of a woven fabric, nonwoven fabric, and the like.
  • an ion exchanger in the form a spacer member such as a diagonal net an ion exchanger comprising a polyolefin resin is preferably used for its excellent ion exchange ability and excellent ability to disperse the water to be treated.
  • a polyethylene diagonal net which is widely employed in electrodialysis baths is used as substrates and ion-exchange ability is imparted by utilizing a radiation-induced graft polymerization, then desirable ion exchanger is obtained.
  • the radiation-induced graft polymerization is a technique for introducing a monomer into polymer substrates by irradiating the polymer with radiation rays so as to produce a radical which reacts with the monomer.
  • Radiation rays usable for the radiation-induced graft polymerization include ⁇ -rays, ⁇ -rays, ⁇ -rays, electron beam, ultraviolet rays, and the like. Of these, ⁇ -rays or electron beam may preferably be used in the present invention.
  • the radiation-induced graft polymerization there are a pre-irradiation graft polymerization comprising previously irradiating graft substrates with radiation rays and then contacting the substrates with a grafting monomer, and a co-irradiation method in which irradiation of radiation rays is carried out in the co-presence of substrates and a grafting monomer. Both of these methods may be employed in the present invention.
  • polymerization methods such as a liquid-phase graft polymerization method in which polymerization is effected while substrates are immersed in a monomer solution, a gas-phase graft polymerization method in which polymerization is effected while substrates are in contact with vapor of monomer, and an immersion gas-phase graft polymerization method in which substrates are firstly immersed in a monomer solution and then taken out of the monomer solution and a polymerization is effected in a gas phase. Either method of polymerization may be employed in the present invention.
  • the ion-exchange groups to be introduced into fibrous substrates such as a nonwoven fabric, or into spacer substrates are not particularly limited.
  • Various kinds of cation-exchange groups and anion-exchange groups can be used.
  • usable cation-exchange groups include strongly acidic cation-exchange groups such as sulfo group, moderately acidic cation-exchange groups such as phosphoric group, and weakly acidic cation-exchange groups such as carboxy group.
  • Usable anion-exchange groups includeweaklybasic anion-exchange groups such as primary, secondary and tertially amino groups, and strongly basic anion-exchange groups such as quaternary ammonium group.
  • an ion exchanger having both of the above-described cation and anion groups may also be employed.
  • an ion exchanger having functional groups such as functional groups derived from iminodiacetic acid or its sodium salt, functional groups derived fromvarious amino acids includingphenylalanine, lysine, leucine, valine, proline or their sodiumsalts or functional groups derived from iminodiethanol .
  • ion-exchange groups can be introduced into fibrous substrates or spacer substrates by subjecting a monomer having such an ion-exchange group to graft polymerization, preferably radiation-induced graft polymerization, or by subjecting a polymerizable monomer having a group that are changeable into an ion-exchange group, to graft polymerization, followed by conversion of that group into the ion-exchange group.
  • Monomers having an ion-exchange group usable for this purpose may include acrylic acid (AAc) , methacrylic acid, sodium styrenesulfonate (SSS) , sodium methallylsulfonate, sodium allylsulfonate, sodium vinylsulfonate, vinylbenzyl trimethylammonium chloride (VBTAC) , diethylaminoethyl methacrylate, and dimethylaminopropylacrylamide.
  • Sulfo group as a strongly acidic cation-exchange group for example, may be introduced directly into substrates by carrying out radiation-induced graft polymerization in which sodium styrenesulfonate is used as amonomer .
  • Quaternary ammoniumgroup as a strongly basic anion-exchange group may be introduced directly into substrates by carrying out radiation-induced graft polymerization in which vinylbenzyl trimethylammonium chloride is used as a monomer.
  • the monomer having groups that can be converted into ion-exchange groups may include acrylonitrile, acrolein, vinylpyridine, styrene, chloromethylstyrene, and glycidyl methacrylate (GMA) .
  • Sulfo group as a strongly acidic cation-exchange group may be introduced into substrates in such a manner that glycidyl methacrylate is introduced into the substrates by radiation-induced graft polymerization, and then react with a sulfonating agent such as sodium sulfite .
  • Quaternary ammonium group as a strongly basic anion-exchange group may be introduced into substrates in such a manner that chloromethylstyrene is graft-polymerized onto substrates and then the substrates are immersed into an aqueous solution of trimethylamine to effect quaternary-ammonification.
  • sodium iminodiacetate group as a functional group can be introduced into substrates in such a manner that chloromethylstyrene is graft-polymerized onto substrates and the substrates react with a sulfide to make a sulfonium salt, and then the sulfonium salt reacts with sodium iminodiacetate.
  • sodium iminodiacetate as a functional group may be introduced into substrates in such a manner that chloromethylstyrene is graft-polymerized onto substrates and chloro group is substituted with iodine group and iodine group reacts with an iminodiacetic acid diethyl ester to substitute iodine group with an iminodiacetic acid diethyl ester group, and finallythe ester group reactswith sodiumhydroxide to convert the ester group into sodium salt.
  • an ion-exchange fibrous material in the form of a nonwoven fabric or awoven fabric is particularlypreferable .
  • Afibrousmaterial, such as a woven fabric or a nonwoven fabric, as compared to materials in the form of beads, a diagonal net, and the like has a remarkably larger surface area, and therefore a larger amount of ion exchange groups can be introduced thereinto.
  • resin beads in which ion-exchange groups are present in micropores or macropores within the beads all the ion-exchange groups are present on the surfaces of fibers in the case of an ion-exchange fibrous material.
  • metal ions in the water to be treated can easily diffuse into the vicinity of ion-exchange groups, and the ions are adsorbed by means of ion exchange. Therefore, the use of an ion-exchange fibrous material can thus improve removal and recovery efficiency of metal ions.
  • waste water which has been subjected to the ⁇ potential converting step 5 or the oxidizing agent decomposition step 2A is received by a coagulating sedimentation tank.
  • a coagulant is added to the water to be treated, whereby metal ions in the water to be treated are coagulated and precipitated, and removed from the water, while the supernatant liquid is recovered as treated water.
  • the metal precipitated in the coagulating sedimentation is recovered as a precipitate and, if necessary, subjected to a subsequent treatment.
  • coagulant to be used in such a system for coagulating sedimentation metal ions in water to be treated various chemicals known in the art as usable for coagulating and precipitating metal ions in an aqueous medium, can be used.
  • specific examples include an alkali such as NaOH, Ca(OH) 2 or KOH, a polymer coagulant, inorganic coagulant such as FeS0 and FeCl 3 .
  • inorganic coagulant containing Fe 2+ such as FeS0 4
  • Fenton reaction occurs, hydrogen peroxide and chelating agent are decomposed.
  • a sludge produced by the coagulating treatment may be filtered through a membrane, such as an MF membrane which is generally used in waste water treatment.
  • Example 1 Provides of cation-exchange nonwoven fabrio
  • nonwoven fabric having the following characteristics was used as a base material for producing a cation-exchange nonwoven fabric.
  • the base nonwoven fabric was formed by thermal fusion of composite fiber which consists of a core portion of polypropylene and a sheath portion of polyethylene.
  • Agamma ray was irradiated to the nonwoven fabric substrates under a nitrogen atmosphere and then immersed into a solution of glycidyl methacrylate (GMA) .
  • GMA glycidyl methacrylate
  • the graft-polymerized nonwoven fabric was immersed into a mixed solution of sodium sulfite, isopropyl alcohol, and water, for sulfonation.
  • a cation-exchange nonwoven fabric was produced.
  • the ion exchange capacity of the cation-exchange nonwoven fabric was measured, it was found that a strongly acidic cation-exchange nonwoven fabric having a salt splitting capacity of 2.82 meq/g was obtained.
  • the reference numeral 134 denotes a cation-exchange membrane
  • 136 denotes treated water
  • 138 denotes concentrated water
  • 141 denotes an electrolytic deposition apparatus
  • 142 denotes water to be treated.
  • the cation-exchange nonwoven fabric having sulfo group was used as an ion exchanger in the desalting chamber 135, and the cation-exchange nonwoven fabric having sulfo group was used as an ion exchanger in the concentrating chamber 137.
  • the cathode 140 was made of expanded metal (material : SUS)
  • the anode 139 was made of expanded metal (material: titanium coated with platinum) .
  • Sulfuric acid was supplied to the cathode chamber so that a pH of the liquid became 1.5 or less.
  • the anode material was titanium coated with platinum, and the cathode material was copper.
  • the bath was stirred at a rotational speed of 300 rpm (m _1 ) by means of a stirrer.
  • Experiment I was carried out using a copper-plating rinsing waste water as raw water.
  • Experiment II was carried out using CMP waste water discharged from a polishing process for polishing copper as raw water.
  • the CMP waste water was treated using a platinum-coated metal honeycomb catalyst so that the remaining H 2 0 2 was reduced to not more than 1 mg/1.
  • the slurry concentration of the CMP waste water was 2000 ppm in terms of TS (Total Solid: Residue, Total, EPA Method 160.3).
  • the current density was set at 3A(ampere) /dm 2 both in the separation treatment and the recovery treatment.
  • the Cu concentration of raw water was 120 ppm, whereas the Cu concentration of treated water was less than 0.1 ppm.
  • the constitution of this Example could also attain the effect of the present invention.
  • the copper ion concentration concentratedinthe concentrating chamber was found to be not less than 1000 ppm.
  • the copper ions in the concentrated water were recovered as coppermetal at the cathode in the recovery treatment step.
  • Slurry-suspended Cu-CMP waste water (TS: 2500 mg/1, Cu concentration: 100 mg/1, H 2 0 2 concentration: 1000 mg/1, ⁇ potential of slurry: minus (negative) value (-20 mV or less) in a pH of 3 to 10 although the ⁇ potential varies depending upon pH) was adjusted to a pH of 5 by the addition of sulfuric acid, and then hydrogen peroxide in the waste water is decomposed in a hydrogen peroxide decomposition apparatus shown in FIG. 3.
  • a catalyst-packed tower having a three-column structure was used.
  • a gas-liquid separator was provided between adjacent columns to remove an oxygen gas generatedby the decomposition of hydrogen peroxide.
  • the treatment was carried out under conditions of water flowing speed 30 m/hour and contact time 3 minutes (in total of three columns) .
  • the catalyst used was a platinum-coatedmetal honeycomb catalyst (having an acid-resistant coating) , and had a pore density of 500 cell/square inch.
  • the amount of platinum coated by the metal honeycomb catalyst was 2 g/1. As a result, the concentration of hydrogenperoxide in the rawwater was reduced to less than 5 mg/1 by the decomposition.
  • Treated water obtained by the hydrogen peroxide decomposition treatment (Cu-CMP waste water, pH unadjusted) was used for a slurry separation test. 50 mg/1 of ferric chloride was added to and mixed with the treated water, and a mixed liquid was treated so that its pH was adjusted to 5 by the addition of KOH. As a result, the mixed liquid containing coagulated floes (SS 2200 mg/1) was obtained. This mixed liquid was allowed to stand for 30 minutes, thus obtaining a clear supernatant liquid containing no slurry. The clear supernatant liquid containing no slurry was also obtained after 3 mg/1 of anionic polymer coagulant was added to the mixed liquid and then the mixed liquid was allowed to stand.
  • the use of the anionic polymer coagulant increased the sedimentation speed of the slurry-containing coagulated floe, and its sedimentation speed was not less than 100 mm/minute (SS concentration after solid-liquid separation ⁇ 10000 mg/1) .
  • the concentration of Cu in the supernatant liquid was 90 mg/1, and it was confirmed that most of copper in the raw water remained in the supernatant liquid.
  • This supernatant liquid was filteredby an organicmembrane filter having a pore diameter of 1.0 ⁇ m, thus obtaining water fromwhich slurrywas separated. Further, even in using a ceramic filter having a pore diameter of 0.1 ⁇ m, it was confirmed that the supernatant liquid could be successfully filtered to give a filtrate.
  • Treated water obtained by the hydrogen peroxide decomposition treatment (Cu-CMP waste water; adjusted to a pH of 5; containing slurry) was used for a Cu treatment test.
  • a Cu treatment apparatus having a construction shown in FIG. 5 was used.
  • the first desalting chamber andthe seconddesalting chamber were packed with a cation-exchange nonwoven fabric.
  • the cation-exchange nonwoven fabric was produced by introducing styrene into a substrate nonwoven fabric (tradename: T6, manufacturedby JapanVilene Co . , Ltd. , core and sheath component : PE) by graft polymerization (graft ratio 107%) and sulfonating the graft-polymerized nonwoven fabric to provide an ion exchange capacity of 650 to 700 meq/m 2 .
  • the cation-exchange nonwoven fabric produced by the graft polymerization, a cation-exchange spacer, and an anion-exchange nonwoven fabric were packed in the concentrating chamber.
  • the Cu recovery step was carried out under conditions of constant-potential operation (cathode potential -0.1 V), cathode: Cu plate (2 dm 2 ), and anode Ti/Pt lath plate (2 dm 2 ) .
  • the pH of both CuS0 4 circulation water and H 2 S0 4 circulation water was 1.5.
  • the concentration of Cu in the treated water was 0.050 mg/1. No adverse effect of the slurry on the treatment capability was observed. Further, it was also confirmed that Cu recovered as CuS0 4 concentrated water was recovered as a Cu metal on the cathode surface in the Cu recovery step. It was also confirmed that the pH of both CuS0 circulation water and H 2 S0 4 circulation water was maintained in the range of 1.4 to 1.6 during operation.
  • Example 4 Copper-containing waste water discharged from a Cu-CMP apparatus and containing 2000 ppm of CMP abrasive particles with a positive value of ⁇ potential ( ⁇ potential: 13 mV, cumulant average particle diameter (hydrodynamic equivalent diameter) : 800 nm, composition: a mixture of Si0 2 and Al 2 0 3 ) and 100 ppm of copper ions was treated with a platinum-coatedmetal honeycomb catalyst shown in FIG.
  • the Cu treatment apparatus was operated under the following conditions: Current density: 3 A/dm 2 SV: 100 1/hour
  • the operating voltage was 20 V in an initial stage of the operation.
  • the operating voltage rose with the elapse of time. After an elapse of 30 minutes from the start of the operation, the operating voltage reached 40 V.
  • the operation was stopped, and the interior of the apparatus for the separation step was inspected. Then, it was found that CMP abrasive particles were deposited on the surface of the ion-exchangemembrane on the cathode side of the desalting chamber. Further, it was confirmed that gelled CMP abrasive particles were deposited on the surface of the cation-exchange nonwoven fabric packed into the desalting chamber.
  • Copper-containing waste water containing 2000 ppm of CMP abrasive particles with a negative value of ⁇ potential ( ⁇ potential: -25 mV, hydrodynamic equivalent diameter: 600 nm, composition: a mixture of Si0 2 and A1 2 0 3 ) and 50 ppm of copper ions was treated with a platinum-coated metal honeycomb catalyst shown in FIG. 3 to reduce the amount of residual H 2 0 2 to less than 1 mg/1, and the treated water was then supplied to a Cu treatment apparatus shown in FIG. 6.
  • Example 6 The operation was carried out under the same conditions as those in Example 1. As a result, the operating voltage was in the range of 20 to 25 V, and the stable operation could be carried out for 24 hours or longer. After the operation was carried out for 24 hours, the interior of the apparatus for the separation step was inspected. Then, the deposition of the abrasive particles and the gelation of the abrasive particles within the desalting chamber were not observed at all. The concentration of Cu in the treated water was less than 0.5 mg/1. Example 6
  • Example 4 The copper-containing waste water used in Example 4 was treated with a platinum-coated catalyst (metal honeycomb catalyst) shown in FIG. 3 to reduce the amount of residual H 2 0 2 to less than 1 mg/1, and 0.5% of chemical stock solution containing an anionic surfactant was then added to the treated water. As a result, the ⁇ potential was -15 mV. Water flowing was carried out using the same Cu treatment apparatus as that in Example 4 under the same operating conditions as those in Example 4. As a result, the operating voltage was in the range of 20 to 25 V, and the stable operation could be carried out for 24 hours or longer. During the operation, the deposition of the abrasive particles and gelation of the abrasive particles within the desalting chamber were not observed.
  • a platinum-coated catalyst metal honeycomb catalyst shown in FIG. 3
  • Example 4 The copper-containing waste water used in Example 4 was treated with a platinum-coated catalyst (metal honeycomb catalyst) shown in FIG. 3 to reduce the amount of residual H 2 0 2 to less than 1 mg/1, and chemical stock solution containing an anionic surfactant different from that of Example 6 was then added to the treated water. By the additive rate of 1.2 %, the ⁇ potential was lowered to -18 mV. Water flowing was carried out using the same Cu treatment apparatus as that in Example 4 under the same operating conditions as those in Example 4. As a result, the operating voltage was in the range of 20 to 25 V, and the stable operation could be carried out for 24 hours or longer. During the operation, the deposition of the abrasive particles and gelation of the abrasive particles within the desalting chamber were not observed. The concentration of Cu in the treated water was less than 0.5 mg/1.
  • Example 8 The concentration of Cu in the treated water was less than 0.5 mg/1.
  • the quality of the treated water was as follows: Cu: less than 0.5 mg/1 at an initial stage of the operation, the Cu treatment capability reduced with the elapse of time, after an elapse of 12 hours from the start of the operation, the concentration of Cu in the treated water increased to 3 mg/1.
  • 0.5% of chemical stock solution containing an anionic surfactant was added to the waste water which had been subjected to H 2 0 2 decomposition treatment in the same manner as Example 6, and then the waste water was supplied to the ion-exchange resin column packed with the strongly acidic cation-exchange resin beads in the same manner as the above. Then, the quality of the treated water was as follows : Cu: less than 0.5 mg/1 even after an elapse of 24 hours from the start of water flowing.
  • Hydrogen peroxide contained in slurry-suspended Cu-CMP waste water (pH: 5, TS (Total Solid) : 2500 mg/1, TSS (Total Solid Soluble) : 500 mg/1, Cu concentration: 100 mg/1, H 2 0 2 concentration: 1200 mg/1, composition of slurry: a mixture of silica and alumina, ⁇ potential of slurry: -20 V), was decomposed in a hydrogen peroxide decomposition apparatus shown in FIG. 3.
  • a catalyst-packed tower was composed of a three-column structure, and a gas-liquid separator was provided between adjacent columns to remove an oxygen gas generated by the decomposition of hydrogen peroxide.
  • the catalyst used was a platinum-coated metal honeycomb catalyst (having an acid-resistant coating) and had a pore density of 500 cell/square inch.
  • the amount of platinum coated by the metal honeycomb catalyst was 2 g/1. .
  • the treatment was carried out under conditions of water flowing speed 30 m/hour and contact time 3 minutes (in total of three columns) . As a result, the concentration of hydrogen peroxide in the raw water was reduced to less than 5 mg/1 by the decomposition.
  • the Cu-CMP waste water was adjusted to a pH of 3 by the addition of sulfuric acid. In this state, the ⁇ potential of the slurry was measured and found to be -15 mV.
  • the Cu-CMP waste water after the addition of the surfactant was used as raw water and was subjected to a treatment test with a Cu treatment apparatus shown in FIG. 6.
  • the treatment was carried out under the following conditions: The treatment operation was continued for 5 days. Then, the operating voltage was stable at a voltage of 25 V, and the quality of the treated water was in the range of 0.1 to 0.3 mg-Cu/1.
  • the concentration of Cu in the CuS0 4 concentrated water was in the range of 80 to 120 mg/1.
  • the electrodialysis apparatus in the separation step was dismantled, and the interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all.
  • a five-day treatment experiment was carried out as a comparative experiment in which no surfactant was added to the Cu-CMP waste water.
  • the experimental apparatus and conditions used were the same as those in the above.
  • the operating voltage rose from 25 V to 35 V, and after the operation of the apparatus, coagulation of the slurry was observed within the first desalting chamber and the second desalting chamber.
  • the addition of the surfactant had the effect of stabilizing the treatment operation.
  • Negative electrode SUS 304 lath-type electrode
  • Anion exchange membrane AHA manufactured by TOKUYAMA Corp.
  • First desalting chamber and second desalting chamber produced by radiation-induced graft polymerization.
  • Substrate nonwoven fabric material PE, functional group: sulfo group
  • Anion-exchange nonwoven fabric produced by radiation-induced graft polymerization.
  • Substrate nonwoven fabric material PP/PE, functional group: quaternary ammonium group •
  • Cation exchange spacer produced by radiation-induced graft polymerization.
  • Substrate spacer PE, functional group: acrylic acid and sulfonic acid
  • Anion exchange spacer produced by radiation-induced graft polymerization.
  • Substrate spacer PE, functional group: quaternary ammonium group Example 11
  • the Cu-CMP waste water, which had been subjected to the hydrogen peroxide decomposition treatment, prepared in Example 10 was adjusted to a pH of 3 by the addition of sulfuric acid and NEOPELEX GS manufactured by Kao Corporation as H-type anionic surfactant having sulfo group.
  • Additive rate of the H-type anionic surfactant was 300 mg/1.
  • the ⁇ potential of the slurry was measured and found to be -30 mV. This value was lower than a ⁇ potential -15 V in a case where only sulfuric acid was used for the pH adjustment.
  • the Cu-CMP waste water after the addition of the surfactant was used as raw water and was subjected to a treatment test with a Cu treatment apparatus shown in FIG. 6.
  • the treatment was carried out under the same conditions as those in Example 10.
  • the treatment operation was continued for 5 days.
  • the operating voltage was stable at a voltage of 25 V, and the quality of the treatedwater was less than 0.1 mg-Cu/1 during the treatment operation.
  • the quality of the treated water was lower than that in Example 10.
  • the electrodialysis apparatus in the separation step was dismantled, and the interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all. Thus, it was confirmed that the utilization of the H-type anionic surfactant further enhanced Cu treatment performance.
  • the Cu-CMP waste water, which had been subjected to the hydrogen peroxide decomposition treatment, prepared in Example 10 was adjusted to a pH of 3 by the addition of sulfuric acid and NEOPELEX GS manufactured by Kao Corporation as H-type anionic surfactant having sulfo group.
  • Additive rate of the H-type anionic surfactant was 300 mg/1.
  • the ⁇ potential of the slurry was measured and found to be -30 mV. This value was lower than a ⁇ potential -15 mV in a case where only sulfuric acid was used for the pH adjustment.
  • the Cu-CMP waste water after the addition of the surfactant was used as raw water and was subjected to a treatment test with a Cu treatment apparatus shown in FIG. 26.
  • the treatment was carried out under the following conditions: The treatment operation was continued for 5 days. Then, the operating voltage was stable at a voltage of 25 V, and the concentration of Cu in the treatedwater was less than 0.1 mg-Cu/1 during the treatment operation. The quality of the treated water was lower than that in Example 10.
  • the electrodialysis apparatus in the separation step was dismantled, and the interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all. Thus, it was confirmed that the use of an integral electrodialysis apparatus shown in FIG. 26, which performs both the separation step and the acid recovery step, was also effective.
  • Electrodialysis apparatus (which performed both separation step and acid recovery step)
  • Negative electrode SUS 304 lath-type electrode
  • Cation exchange membrane CMB manufactured by TOKUYAMA Corp.
  • Anion exchange membrane AHA manufactured by TOKUYAMA Corp.
  • First desalting chamber and second desalting chamber produced by radiation-induced graft polymerization.
  • Substrate nonwoven fabric material PE, functional group: sulfo group
  • Anion-exchange nonwoven fabric produced by radiation-induced graft polymerization.
  • Substrate nonwoven fabric material PP/PE, functional group: quaternary ammonium group
  • Cation exchange spacer produced by radiation-induced graft polymerization.
  • Substrate spacer PE, functional group: acrylic acid and sulfonic acid
  • Anion exchange spacer produced by radiation-induced graft polymerization.
  • Substrate spacer PE, functional group: quaternary ammonium group Example 13
  • the Cu-CMP waste water, which had been subjected to the hydrogen peroxide decomposition treatment, prepared in Example 10 was adjusted to a pH of 3 by the addition of sulfuric acid andEMULGEN 1118 S-70manufacturedbyKao Corporation as anonionic surfactant.
  • Additive rate of the nonionic surfactant was 300 mg/1.
  • the ⁇ potential of the slurry was measured and found to be in the range of 0 to -10 mV.
  • the Cu-CMP waste water after the addition of the surfactant was used as raw water and was subjected to a treatment test with a Cu treatment apparatus shown in FIG. 6. The treatment was carried out under the same conditions as those in Example 10. The treatment operation was continued for 5 days .
  • Example 14 the operating voltage was stable at a voltage of 23 V, and the concentration of Cu in the treated water was less than 0.1 mg-Cu/1 during the treatment operation.
  • the quality of the treated water was lower than that in Example 10.
  • the electrodialysis apparatus in the separation step was dismantled, and the interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all. Thus, it was confirmed that the utilization of the nonionic surfactant further enhanced Cu treatment performance.
  • Example 14 the electrodialysis apparatus in the separation step was dismantled, and the interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all. Thus, it was confirmed that the utilization of the nonionic surfactant further enhanced Cu treatment performance.
  • the Cu-CMP waste water, which had been subjected to the hydrogen peroxide decomposition treatment, prepared in Example 10 was adjusted to a pH of 3 by the addition of sulfuric acid and NEOPELEX GS manufactured by Kao Corporation as H-type anionic surfactant having sulfo group.
  • Additive rate of the H-type anionic surfactant was 300 mg/1.
  • the Cu-CMP waste water to which the surfactant had been added was prepared as rawwater andwas supplied to an ion exchange resin column packed with strongly acidic cation-exchange resin beads.
  • the water flowing speed was LV 30 m/hour.
  • the concentration of Cu in the treated water was less than 0.5 mg/1 even after water flowing for 24 hours.
  • the Cu-CMP waste water, which had been subjected to the hydrogen peroxide decomposition treatment, prepared in Example 10 was adjusted by the addition of anionic surfactant having sulfo group (POLITY PS-1900, manufactured by Lion Corporation) .
  • Additive rate of the anionic surfactant was 300 mg/1.
  • the Cu-CMP waste water to which the surfactant had been added was prepared as raw water andwas supplied to an ion exchange resin column packed with cation-exchange resin beads having iminodiacetic acid group.
  • the water flowing speed was LV 30 m/hour.
  • the concentration of Cu in the treatedwater was less than 0.5 mg/1 even after water flowing for 24 hours.
  • Example 16 NEOPELEX GS manufactured by Kao Corporation as H-type anionic surfactant having sulfo group was added to the Cu-CMP waste water, which had been subjected to the hydrogen peroxide decomposition treatment, prepared in Example 10. Additive rate of the H-type anionic surfactant was 300 mg/1.
  • the Cu-CMP waste water to which the surfactant had been added was prepared as rawwater and was supplied to an ion exchange resin column packed with cation-exchange resin beads having iminodiacetic acid group.
  • the water flowing speed was LV 30 m/hour.
  • the concentration of Cu in the treatedwater was less than 0.5 mg/1 even after water flowing for 24 hours.
  • a Cu-CMP apparatus as shown in FIG. 28A comprising a Cu polishing unit and a barrier-layer polishing unit which have respective turntables
  • waste water discharged only from the Cu polishing unit was collected and used as raw water.
  • the TS (total 'solid) value was 5000 mg/1
  • the Cu concentration was 150 mg/1
  • the H 2 0 2 concentration was 1400 mg/1
  • the main component of the slurry was silica
  • the ⁇ potential of the slurry was -20 mV.
  • the hydrogen peroxide was decomposedusing the same hydrogenperoxide decomposition apparatus as that in Example 10.
  • the catalyst used was a platinum-coated metal honeycomb catalyst (having an acid-resistant coating) , and had a pore density of 500 cell/square inch.
  • the amount of platinum coated by the metal honeycomb catalyst was 5 g/1.
  • the treatment was carried out under conditions of water flowing speed 30 m/hour and contact time 3 minutes (in total of three columns) . As a result, the concentration of hydrogen peroxide in the raw water was reduced to less than 5 mg/1 by the decomposition.
  • the waste water which had been subjected to the hydrogen peroxide decomposition treatment, was adjusted to a pH of 3 by the addition of sulfuric acid and NEOPELEX GS manufactured by Kao Corporation as H-type anionic surfactant having sulfo group.
  • Additive rate of the H-type anionic surfactant was 300 mg/1.
  • the ⁇ potential of the slurry was measured and found to be -30 mV. This value was lower than a ⁇ potential -15 mV in a casewhere only sulfuric acidwas used for thepH adjustment.
  • the Cu-CMP waste water after the addition of the surfactant was used as raw water and was subjected to a treatment test with a Cu treatment apparatus shown in FIG. 6.
  • Example 18 The treatment was carried out under the same conditions as those in Example 10. The treatment operation was continued for 5 days. Then, the operating voltage was stable at a voltage of 20 V, and the concentration of Cu in the treatedwaterwas less than 0.5mg-Cu/l. After the operation of the apparatus, the electrodialysis apparatus in the separation stepwas dismantled, andthe interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all. Thus, it was confirmed that good results could be obtained even when the waste water to be. treated was only waste water discharged from the Cu polishing step carried out by the Cu-CMP apparatus. Example 18
  • waste water discharged only from the Cu polishing step was collected and used as raw water.
  • the TS (total solid) value was 3000 mg/1
  • the Cu concentration was 150 mg/1
  • the H 2 0 2 concentration was 2000 mg/1
  • the main component of the slurry was silica
  • the ⁇ potential of the slurry was -20 mV.
  • the hydrogenperoxide was decomposedusing the same hydrogen peroxide decomposition apparatus as that in Example 10.
  • the catalyst used was a platinum-coated metal honeycomb catalyst (having an acid-resistant coating) , and had a pore density of 500 cell/square inch.
  • the amount of platinum coated by the metal honeycomb catalyst was 5 g/1.
  • the treatment was carried out under conditions of water flowing speed 30 m/hour and contact time 3 minutes (in total of three columns) . As a result, the concentration of hydrogen peroxide in the raw water was reduced to less than 5 mg/1 by the decomposition.
  • the waste water which had been subjected to the hydrogen peroxide decomposition treatment, was adjusted to a pH of 3 by the addition of sulfuric acid and NEOPELEX GS manufactured by Kao Corporation as H-type anionic surfactant having sulfo group.
  • Additive rate of the H-type anionic surfactant was 300 mg/1.
  • the ⁇ potential of the slurry was measured and found to be -35 mV. This value was lower than a ⁇ potential -15 mVi a case where only sulfuric acidwas used for thepH adjustment .
  • the Cu-CMP waste water after the addition of the surfactant was used as raw water and was subjected to a treatment test with a Cu treatment apparatus shown in FIG. 6.
  • the treatment was carried out under the same conditions as those in Example 10.
  • the treatment operation was continued for 5 days.
  • the operating voltage was stable at a voltage of 20 V, and the concentration of Cu in the treatedwater was less than 0.5mg-Cu/l.
  • the electrodialysis apparatus in the separation step was dismantled, and the interiors of the first desalting chamber and the second desalting chamber were inspected. As a result, it was confirmed that there was no coagulation of the slurry at all.
  • water to be treated containing copper
  • the copper can be recovered in the form of metal element.
  • waste water discharged from a semiconductor fabrication process e.g., a CMP process or a copper plating process
  • a semiconductor fabrication process e.g., a CMP process or a copper plating process
  • copper can be recovered as coppermetal fromthe waste water. Therefore, the present invention is extremely effective in view of discharge limit and resource saving.
  • the present invention is suitable for use in a method and apparatus for removing and recovering metal such as copper from various kinds of waste water discharged from a CMP step, a copper plating step, or the like.

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