US3855141A - Method of processing a spent copper etching solution for reuse in an electroless copper recovery baths - Google Patents
Method of processing a spent copper etching solution for reuse in an electroless copper recovery baths Download PDFInfo
- Publication number
- US3855141A US3855141A US00390553A US39055373A US3855141A US 3855141 A US3855141 A US 3855141A US 00390553 A US00390553 A US 00390553A US 39055373 A US39055373 A US 39055373A US 3855141 A US3855141 A US 3855141A
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- US
- United States
- Prior art keywords
- copper
- solution
- spent
- concentration
- cucl
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/38—Coating with copper
Definitions
- the spent solution is enriched by p l the addition of copper ions which are oxidized in the [57] Us Cl 252/792 156/19 252/794 presence of an alkaline complex component to in- 6 3 3/00 6 crease the concentration of CuCl in the solution and [58] Fie'ld 252/79 79 2 79 to thereby decrease the concentration of CuCl.
- the spent solution is first enriched by the addition of copper ions to a predetermined specified concentration.
- An oxidation medium such as hydrogen peroxide
- an alkaline complex component illustrated as ethylenediaminetetraacetic acid, hereinafter called EDTA
- EDTA ethylenediaminetetraacetic acid
- FIGURE is a diagram showing facilities for preparing spent copper etching solution in accordance with the invention.
- a copper etching operation carried out in a conventional etching tank 1 may typically employ a starting solution that includes copper chloride (CuCl having a copper concentration in the range of 30 grams.
- CuCl copper chloride having a copper concentration in the range of 30 grams.
- the spent solution from the etching tank 1 is conducted via a magnetic valve 2 and to a first mixing vessel 3 where it is enriched to a'prescribed copper concentration by theaddition of copper ions from a suitable source 11.
- the concentration of CuCl in the enriched solution may be analytically determined.
- an oxidizing agent (illustratively hydrogen peroxide) from a source 12 together with an alkaline complex component (illustratively EDTA) from a source 13 are then added to the enriched solution in a second mixing vessel 5.
- the resulting oxidation of the added copper serves to increase the concentration of the unsaturated CuCl component in the solution, in accordance with the following equation:
- the relative amounts of the oxidizing agent and the alkaline complex component are determined in a conventional way in accordance with the previously measured concentration of CuCl in the enriched solution, although it has been found that when the oxidization agent is added in excess of such predetermined amount, improved performance is obtained in some cases
- the EDTA added during the same step preferably has a pH in the range of 11.5 to 12.5 to prevent hydroxide formation. Care must be taken to assure that the elevated temperatures generates in the vessel 5 generated during oxidation does not impair the efficiency of the EDTA.
- oxygen e.g., a chlorate
- free oxygen may be used as the oxidizing agent in the mixing vessel 5.
- alkaline complex components other than EDTA e.g., nitriloessic acid or triethanolamine
- EDTA nitriloessic acid or triethanolamine
- the regenerated etching solution is applied through a filter 7 into an electroless copper recovery tank 8 (together with suitable stabilizers, if necessary.) whereupon efficient recovery of the etched copper from the regenerated, alkaline solution may be accomplished without the requirement of extraction of impurities and other contaminants as in electrolytic processes.
- a method of preparing the spent etching solution for reuse in the separation of the etched copper by electroless means which comprises the steps of:
- oxidizing agent is selected from the group consisting of hydrogen peroxide, free oxygen, and a chlorate.
- alkaline complex component is selected from the group consisting of EDTA, nitriloessic acid and thriethanolamine.
Abstract
Process improvements are described for obtaining long term stability during the electroless recovery of etched copper from a spent acidic copper chloride etching solution having a large concentration of a CuCl component. The spent solution is enriched by the addition of copper ions which are oxidized in the presence of an alkaline complex component to increase the concentration of CuCl2 in the solution and to thereby decrease the concentration of CuCl.
Description
Elnited States Patent [191 Ruff [ METHOD OF PROCESSING A SPENT COPPER ETCHING SOLUTION FOR REUSE IN AN ELECTROLESS COPPER RECOVERY BATHS [75] Inventor: Claus Werner Ruff, Lichtenfels,
Germany [73} Assignee: Loewe-Opta GmbH, Berlin, Germany [22] Filed: Aug. 22, 1973 [21] Appl. No.1 390,553
[451 Dec. 17, 1974 [56] References Cited UNITED STATES PATENTS 3,438,901 4/1969 Vassileff 252/793 3,600,244 8/1971 Wegener 156/19 Primary EraminerWilliam A. Powell Attorney, Agent, or FirmArthur O. Klein [57] ABSTRACT 7 Process improvements are described for obtaining long term stability during the electroless recovery of etched copper from a spent acidic copper chloride 30 Foreign Application priority Data etching so1ution having a large concentration of a Se 1 9 1977 Germany 2244307 CuCl component. The spent solution is enriched by p l the addition of copper ions which are oxidized in the [57] Us Cl 252/792 156/19 252/794 presence of an alkaline complex component to in- 6 3 3/00 6 crease the concentration of CuCl in the solution and [58] Fie'ld 252/79 79 2 79 to thereby decrease the concentration of CuCl.
1 56/18, 19 4 Claims, 1 Drawing Figure 'flfl/ ffi OX/D/Z/WG m/r iii/Kr 5020/01 saui'cz l 7 15256590 fif/X/AG' M/X/AG 5 v5s2 v5s2 Y Aa icavffi) lEEIHiI 1. Z w i l 45 Cfi/VPAf/l /3 Ca/vPw/arr sawed:-
METHOD OF PROCESSING A SPENT COPPER ETCHING SOLUTION FOR REUSE IN AN ELE'CTROLESS COPPER RECOVERY BATI-IS BACKGROUND OF THE INVENTION During a typical copper etching operation which employs copper chloride in the form of CuCl in the starting solution along with the salt of an acid (e.g. HCl), at least a portion of the CuCI is converted into CuCl as metallic copper accumulates in the solution during the etch.
In order to advantageously employ auto-catalytic electroless techniques for recovery of the copper in the spent solution, a relatively low concentration of the saturated CuCl constituent should be present therein. Unfortunately, in the normal case the concentration of the saturated CuCl component is too high to produce sta ble long-term recovery of copper by the electroless method. As a result, it has been necessary as a practical matter to recover the copper directly from the spent etching solution by the use of relatively expensive electrolytic techniques, which in general require additional facilities for extracting impurities and other deposits from the electrolytic recovery bath.
SUMMARY OF THE INVENTION These drawbacks are eliminated in accordance with the invention, which contemplates an improved technique for preparing such spent copper etching solution for reuse in electroless regeneration of the etched copper present in the solution.
In an illustrative technique, the spent solution is first enriched by the addition of copper ions to a predetermined specified concentration. An oxidation medium (such as hydrogen peroxide) is then added to the enriched solution along with an alkaline complex component (illustratively ethylenediaminetetraacetic acid, hereinafter called EDTA) having a pH preferably in the range of 11.5 to 12.5. The resulting oxidation increases the CuClconstituent of the etching solution at the expense of the saturated CuCl constituent so that the solution may now be efficiently used for the electroless separation of copper.
BRIEF DESCRIPTION OF THE DRAWING The invention is further set forth in the following detailed description taken in conjunction with the appended drawing, in which the single FIGURE is a diagram showing facilities for preparing spent copper etching solution in accordance with the invention.
DETAILED DESCRIPTION A copper etching operation carried out in a conventional etching tank 1 may typically employ a starting solution that includes copper chloride (CuCl having a copper concentration in the range of 30 grams.
per liter, together with a salt of an acid such as HCl.
During the etching of copper from the work piece (not shown) in the tank 1 etched copper enters the solution and serves to transform a portion of the starting CuCl; constituent in the solution to CuCl in accordance with the reversible equation Cu CuC1 3 2 CuCl 2 CuCl 2 HCL H 0 2 CuCl 2 H 0 As the etch proceeds, however, the concentration of copper in the solution rises to a relatively high value (e.g., in the range of -140 grams per liter) and the solution becomes spent. At this point, the CuCl component is normally too large relative to the CuCl component to permit efficient electroless separation of the etched copper.
In-accordance with the invention, electroless recovery of the etched copper from the spent solution (which now contains constituents of CuCl, CuCl HCl, H 0 and H 0) is facilitated by the procedure to be described.
In particular, the spent solution from the etching tank 1 is conducted via a magnetic valve 2 and to a first mixing vessel 3 where it is enriched to a'prescribed copper concentration by theaddition of copper ions from a suitable source 11. At this point, the concentration of CuCl in the enriched solution may be analytically determined.
Next, an oxidizing agent (illustratively hydrogen peroxide) from a source 12 together with an alkaline complex component (illustratively EDTA) from a source 13 are then added to the enriched solution in a second mixing vessel 5. The resulting oxidation of the added copper serves to increase the concentration of the unsaturated CuCl component in the solution, in accordance with the following equation:
Cu 2 HC1+ H 0 cuci, H20
The relative amounts of the oxidizing agent and the alkaline complex component are determined in a conventional way in accordance with the previously measured concentration of CuCl in the enriched solution, although it has been found that when the oxidization agent is added in excess of such predetermined amount, improved performance is obtained in some cases Also, the EDTA added during the same step preferably has a pH in the range of 11.5 to 12.5 to prevent hydroxide formation. Care must be taken to assure that the elevated temperatures generates in the vessel 5 generated during oxidation does not impair the efficiency of the EDTA.
Other combined forms of oxygen (e.g., a chlorate) as well as free oxygen may be used as the oxidizing agent in the mixing vessel 5. Additionally, alkaline complex components other than EDTA (e.g., nitriloessic acid or triethanolamine) may be used.
From the vessel 5, the regenerated etching solution is applied through a filter 7 into an electroless copper recovery tank 8 (together with suitable stabilizers, if necessary.) whereupon efficient recovery of the etched copper from the regenerated, alkaline solution may be accomplished without the requirement of extraction of impurities and other contaminants as in electrolytic processes.
What is claimed is:
1. For use in the recovery of copper that is etched with the use of an acidic solution containing CuCl wherein a portion of the CuCl, is converted into CuCl during such etching operation as the solution becomes spent, a method of preparing the spent etching solution for reuse in the separation of the etched copper by electroless means which comprises the steps of:
adding copper ions to the spent solutionto a predetermined copper concentration suitable for electroless copper separation; and thereafter adding to the enriched solution an oxidizing agent and an alkaline complex component in amounts respectively effective to (1)- oxidize the added copper to increase the concentration of CuCl in the solution and correspondingly decrease the concentration of CuCl, and (2) to convert the etching solution into an alkaline bath.
2. A method as defined in claim 1, in which the alkaline complex component has a pH in the range between 11.5 and 12.5. 1
3. A method as defined in claim 1, in which the oxidizing agent is selected from the group consisting of hydrogen peroxide, free oxygen, and a chlorate.
4. A method as defined in claim 1, in which the alkaline complex component is selected from the group consisting of EDTA, nitriloessic acid and thriethanolamine. 1
Claims (4)
1. FOR USE IN THE RECOVERY OF COPPER THAT IS ETCHED WITH TTHE USE OF AN ACIDIC SOLUTION CONTAINING CUC12 WHEREIN A PORTION OF THE CUCI2 IS CONVERTED INTO CUCI DURING SUCH ETCHING OPERATION AS THE SOLUTION BECOMES SPENT, A METHOD OF PREPARING THE SPENT ETCHING SOLUTION FOR REUSE IN THE SPARATION OF THE ETCHED COPPER BY ELECTROLESS MEANS WHICH COMPRISES THE STEPS OF ADDING COPPER IONS TO THE SPENT SOLUTION TO A PREDETERMINED SEPARATION; AND THEREAFTER ADDING TO THE ENRICHED SOLUTION COPPER CONCENTRATION SUITABLE FOR ELECTROLESS COPPER AN OXIDIZING AGENT AND AN ALKALINE COMPLEX COMPONENT ON AMOUNTS RESPCTIVELY EFFECTIVE TO (1) OXIDIZE THE ADDED COPPER TO INCREASE THE CONCENTRATION OF CU-CI2 IN THE SOLUTION AND CORRESPO NDING DECREASE THE CONCENTRATION OF CUCI, AND (20 TO CONVERT THE ETCHING SOLUTION INTO AN ALKALINE BATH.
2. A method as defined in claim 1, in which the alkaline complex component has a pH in the range between 11.5 and 12.5.
3. A method as defined in claim 1, in which the oxidizing agent is selected from the group consisting of hydrogen peroxide, free oxygen, and a chlorate.
4. A method as defined in claim 1, in which the alkaline complex component is selected from the group consisting of EDTA, nitriloessic acid and thriethanolamine.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19722244307 DE2244307C3 (en) | 1972-09-09 | Process for the production of alkaline baths for the autocatalytic electroless deposition of copper |
Publications (1)
Publication Number | Publication Date |
---|---|
US3855141A true US3855141A (en) | 1974-12-17 |
Family
ID=5855884
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00390553A Expired - Lifetime US3855141A (en) | 1972-09-09 | 1973-08-22 | Method of processing a spent copper etching solution for reuse in an electroless copper recovery baths |
Country Status (8)
Country | Link |
---|---|
US (1) | US3855141A (en) |
JP (1) | JPS5549155B2 (en) |
AT (1) | AT324065B (en) |
CH (1) | CH606470A5 (en) |
FR (1) | FR2199009B1 (en) |
GB (1) | GB1416637A (en) |
IT (1) | IT993886B (en) |
SE (1) | SE387966B (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3919100A (en) * | 1974-04-24 | 1975-11-11 | Enthone | Alkaline etchant compositions |
US4051001A (en) * | 1974-08-26 | 1977-09-27 | Hitachi, Ltd. | Process for regenerating etching solution |
US5013395A (en) * | 1987-08-28 | 1991-05-07 | International Business Machines Corporation | Continuous regeneration of acid solution |
US5145553A (en) * | 1991-05-06 | 1992-09-08 | International Business Machines Corporation | Method of making a flexible circuit member |
US5227010A (en) * | 1991-04-03 | 1993-07-13 | International Business Machines Corporation | Regeneration of ferric chloride etchants |
US6503363B2 (en) * | 2000-03-03 | 2003-01-07 | Seh America, Inc. | System for reducing wafer contamination using freshly, conditioned alkaline etching solution |
US20050145580A1 (en) * | 2001-10-02 | 2005-07-07 | Rotometrics | Method and apparatus to clean particulate matter from a toxic fluid |
US20110000884A1 (en) * | 2007-07-11 | 2011-01-06 | Harald Ottertun | Method for Etching Copper and Recovery of the Spent Etching Solution |
US20200039852A1 (en) * | 2018-08-02 | 2020-02-06 | Guangzhou Ultra Union Chemicals Ltd | Method for treating electroless copper plating wastewater |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2917597A1 (en) * | 1979-04-30 | 1980-11-13 | Siemens Ag | METHOD FOR REGENERATING AMMONIACAL ETCH SOLUTIONS FOR ETCHING METALLIC COPPER |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3438901A (en) * | 1965-10-22 | 1969-04-15 | Neiko I Vassileff | Metal treating bath and chelating agent for metal reactive acid baths |
US3600244A (en) * | 1969-02-20 | 1971-08-17 | Ibm | Process of etching metal with recovery or regeneration and recycling |
-
1973
- 1973-07-10 SE SE7309677A patent/SE387966B/en unknown
- 1973-07-13 CH CH1023273A patent/CH606470A5/xx not_active IP Right Cessation
- 1973-08-09 AT AT700673A patent/AT324065B/en not_active IP Right Cessation
- 1973-08-22 US US00390553A patent/US3855141A/en not_active Expired - Lifetime
- 1973-09-05 GB GB4171273A patent/GB1416637A/en not_active Expired
- 1973-09-06 FR FR7332189A patent/FR2199009B1/fr not_active Expired
- 1973-09-06 IT IT28632/73A patent/IT993886B/en active
- 1973-09-07 JP JP10040073A patent/JPS5549155B2/ja not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3438901A (en) * | 1965-10-22 | 1969-04-15 | Neiko I Vassileff | Metal treating bath and chelating agent for metal reactive acid baths |
US3600244A (en) * | 1969-02-20 | 1971-08-17 | Ibm | Process of etching metal with recovery or regeneration and recycling |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3919100A (en) * | 1974-04-24 | 1975-11-11 | Enthone | Alkaline etchant compositions |
US4051001A (en) * | 1974-08-26 | 1977-09-27 | Hitachi, Ltd. | Process for regenerating etching solution |
US5013395A (en) * | 1987-08-28 | 1991-05-07 | International Business Machines Corporation | Continuous regeneration of acid solution |
US5227010A (en) * | 1991-04-03 | 1993-07-13 | International Business Machines Corporation | Regeneration of ferric chloride etchants |
US5145553A (en) * | 1991-05-06 | 1992-09-08 | International Business Machines Corporation | Method of making a flexible circuit member |
US6503363B2 (en) * | 2000-03-03 | 2003-01-07 | Seh America, Inc. | System for reducing wafer contamination using freshly, conditioned alkaline etching solution |
US20050145580A1 (en) * | 2001-10-02 | 2005-07-07 | Rotometrics | Method and apparatus to clean particulate matter from a toxic fluid |
US7404904B2 (en) * | 2001-10-02 | 2008-07-29 | Melvin Stanley | Method and apparatus to clean particulate matter from a toxic fluid |
US20110000884A1 (en) * | 2007-07-11 | 2011-01-06 | Harald Ottertun | Method for Etching Copper and Recovery of the Spent Etching Solution |
US8236189B2 (en) * | 2007-07-11 | 2012-08-07 | Sigma Engineering Ab | Method for etching copper and recovery of the spent etching solution |
US20200039852A1 (en) * | 2018-08-02 | 2020-02-06 | Guangzhou Ultra Union Chemicals Ltd | Method for treating electroless copper plating wastewater |
US10577265B2 (en) * | 2018-08-02 | 2020-03-03 | Guangzhou Ultra Union Chemicals Ltd | Method for treating electroless copper plating wastewater |
Also Published As
Publication number | Publication date |
---|---|
JPS50110948A (en) | 1975-09-01 |
JPS5549155B2 (en) | 1980-12-10 |
CH606470A5 (en) | 1978-10-31 |
SE387966B (en) | 1976-09-20 |
DE2244307A1 (en) | 1974-03-28 |
GB1416637A (en) | 1975-12-03 |
AT324065B (en) | 1975-08-11 |
FR2199009B1 (en) | 1978-03-10 |
IT993886B (en) | 1975-09-30 |
FR2199009A1 (en) | 1974-04-05 |
DE2244307B2 (en) | 1975-08-21 |
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