EP0240589B1 - Procédé et appareillage pour la régénération d'un bain de dépôt chimique de cuivre - Google Patents

Procédé et appareillage pour la régénération d'un bain de dépôt chimique de cuivre Download PDF

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Publication number
EP0240589B1
EP0240589B1 EP86105002A EP86105002A EP0240589B1 EP 0240589 B1 EP0240589 B1 EP 0240589B1 EP 86105002 A EP86105002 A EP 86105002A EP 86105002 A EP86105002 A EP 86105002A EP 0240589 B1 EP0240589 B1 EP 0240589B1
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EP
European Patent Office
Prior art keywords
electrolysis
bath
copper
process according
plating bath
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP86105002A
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German (de)
English (en)
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EP0240589A1 (fr
Inventor
Werner D. Bissinger
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IBM Deutschland GmbH
International Business Machines Corp
Original Assignee
IBM Deutschland GmbH
International Business Machines Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by IBM Deutschland GmbH, International Business Machines Corp filed Critical IBM Deutschland GmbH
Priority to DE8686105002T priority Critical patent/DE3668914D1/de
Priority to EP86105002A priority patent/EP0240589B1/fr
Priority to JP62035963A priority patent/JPS62243776A/ja
Priority to US07/033,387 priority patent/US4734175A/en
Publication of EP0240589A1 publication Critical patent/EP0240589A1/fr
Application granted granted Critical
Publication of EP0240589B1 publication Critical patent/EP0240589B1/fr
Anticipated expiration legal-status Critical
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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
    • C23C18/1601—Process or apparatus
    • C23C18/1617—Purification and regeneration of coating baths

Definitions

  • the invention relates to a method for regenerating an electroless copper plating bath which contains a complexing agent such as ethylenediaminetetraacetic acid or the like.
  • the copper film deposited by the electroless process In order for the copper film deposited by the electroless process to have excellent physical properties, compared to those electrolessly deposited films which only act as a conductive thin film for a lead-through opening and are produced by the subtractive process and on which copper is built up by electrolytic deposition, it is necessary to Control the composition of the electroless copper plating bath as closely as possible so that its concentration is as uniform as possible and to keep the formation of by-products as low as possible. The latter is particularly important when recovering the complexing agent, preferably ethylenediaminetetraacetic acid, which is present in high concentrations in the electroless copper plating bath.
  • the complexing agent preferably ethylenediaminetetraacetic acid
  • FR-A 2 386 491 describes a process for the recovery of bath constituents of aqueous electroless metallization baths, in which the copper content of an exhausted copper plating bath is reduced by precipitation of the copper as metallic copper and the complexing agent is precipitated by acidification.
  • the precipitated EDTA is dissolved in NaOH and recycled.
  • the aqueous residue of the bath which still contains about 1 g / l EDTA and 10 mg / l Cu, is subjected to electrolysis, in which the remaining EDTA decomposes and the remaining copper is deposited on the cathode.
  • German Offenlegungsschrift 3 340 305 describes a process for the disposal of chemical metallization baths, in which the heavy metal is removed from the solution by selectively working ion exchangers and the residual solution containing complexing agents can be worked up further.
  • this method is only applicable to the separation of metals from solutions containing complexing agents whose complexing constant is lower than that of the exchange resin. This is not the case for EDTA.
  • the object of the invention is to provide a process for the regeneration of electroless copper plating baths, in which the copper content of the bath is lowered by electrolysis and the conditions for carrying it out are chosen such that a very pure complexing agent, in particular a very complex one, in the further processing of the residual complexing agent solution pure ethylenediaminetetraacetic acid, which is free of by-products, is obtained.
  • the object of the invention is achieved by a method according to claim 1.
  • a container 15 with connecting lines 14 between the two containers is provided for emptying the copper-plating container 11 for cleaning purposes.
  • a pipeline 16 leads from the copper-plating tank 11 to the collecting tank 17. From there, the copper-plating bath to be regenerated reaches the electrolysis unit 19 via feed line 18, in which two electrode blocks 20 and 21 are arranged.
  • the electrolysis unit 19 is provided with overflow boxes 22, a pH measuring probe 24 being installed in one and the addition of sodium hydroxide solution for setting and maintaining the pH value via line 23 into the opposite box.
  • the circulation of the copper bath to be regenerated within the electrolysis unit is described separately with reference to FIG. 5.
  • the number and dimensions of the electrodes in each electrode block are calculated from the current intensity I, the current density i and the container size.
  • the electrodes are mutually arranged in such a way that there is always a cathode between two anodes.
  • the cathodes consist of thin copper foils, the anodes made of stainless steel.
  • the demetallized bath solution passes through pipeline 25 from the electrolysis unit into a container 26 in which the complexing agent is dropped out into the acidic range by lowering the pH.
  • an acid such as sulfuric acid, hydrochloric acid or the like is metered into the container 26 via the line 27.
  • the pH range suitable for the precipitation is generally below 4.0 and for ED-TA below 2.0, preferably below 1.0.
  • EDTA ethylenediaminetetraacetic acid
  • other complexing agents which are suitable for electroless copper plating can also be worked up, for example potassium sodium tartrate (Rochelle salt), ethylenediaminetetramine, triethanolamine, diethanolamine and the like.
  • the precipitated EDTA is washed twice with deionized water, the washing water being fed into the container 32 via the pipeline 31.
  • the EDTA can then be dissolved again in sodium hydroxide solution as the tetrasodium salt and purified by reprecipitation with H 2 S0 4 .
  • the purified ethylenediaminetetraacetic acid is dissolved in the same container (26) in sodium hydroxide solution, which is metered in via line 30, to the tetrasodium salt.
  • the solution of EDTA-NA 4 (tetrasodium edetate) arrives in a storage container 29 and is then fed via line 13 directly into the chemical copper plating bath 12, or a premix with copper sulfate solution is prepared, which then also forms the chemical copper plating bath 12 is supplied in the container 11.
  • an electroless copper plating bath is used with the following components, ranges and parameters:
  • the concentrations of the baths are adjusted by adding separately prepared copper sulfate solution, formalin, sodium cyanide solution and sodium hydroxide solution to the bath when their concentration has fallen below a certain value.
  • the concentrations of the individual bath components are carefully monitored, those of Cu ++, for example, by photometric measurement; that of formaldehyde via a reaction with sodium sulfite, which leads to a change in pH; that of NaCN with an ion-selective electrode and that of NaOH with a glass electrode.
  • the temperature of the bath must also be carefully monitored.
  • the reaction products from the electroless copper plating of activated surfaces of printed circuit boards are essentially Na 2 S0 4 (sodium sulfate) and HCOONa (sodium formate), which reach a constant concentration during the use of the bath.
  • the copper content of the bath liquid is first reduced to a concentration below about 20 by electrolysis mg / I lowered and then the complexing agent precipitated by acidification.
  • the decomposition products I represented by the formula in FIG. 2 and the amines II formed by recombination of free radicals could be detected by numerous laboratory tests. Specifically, these are: tetramethylethylenediamine (a), dimethylethylamine (b), N-methyl-N'-dimethyldiaminomethane (c), ethylenediamine (d) and cyclic amines (e).
  • glycine (f), iminodiacetic acid (g) and the like could be detected.
  • amines in particular ethylenediamine (d)
  • this has a negative effect on the grain structure of the deposited copper layer.
  • a coarse-grained copper layer is deposited from the copper plating bath, in which cracks can form when heated later, for example during soldering.
  • amines can react with other components of the bath, for example with formaldehyde, to give s-triazine derivatives.
  • s-triazine which has a stabilizing effect on formaldehyde, also has a negative effect on the grain structure of the deposited copper layer.
  • the reactions at the cathode and anode are shown in a highly simplified manner in FIG. 3. Due to the galvanic deposition of copper on the cathodes, the electrolyte is constantly depleted of copper ions until the electrolysis is stopped at a residual content of about 20 mg / l Cu. In practice, the copper content of the electrolyte is continuously measured during the electrolysis. The system switches off automatically when the desired final value is reached.
  • the electrodes By covering the electrodes with hydrogen or oxygen during the electrolysis, they become gas electrodes, the electromotive force of which counteracts the copper deposition: and The main reaction: the EMF acts, which is a function of
  • the removal of the gases from the electrodes is best accomplished by high internal bath circulation during the electrolysis, with the electrolyte being circulated with an electrolyte movement of approximately 10 to 50 volumes per hour in the case of a high bath circulation.
  • an electrolyte circulation volume of 300 m3 per hour must be circulated with an electrolyte movement of 20 volumes per hour.
  • FIG. 5 shows a device in which the electrolyte circulation is brought about by blow-in tubes which are arranged under the electrodes.
  • the electrolyte arrives from the electrolysis cell in overflow boxes which are arranged on both sides of this electrolysis unit and is returned from there to the injection tubes.
  • a side view of an electrolysis unit with an electrolysis cell and two overflow boxes and blow-in tubes is shown below the electrodes.
  • a buffer tank (not shown) next to the electrolysis unit, into which the electrolyte is led from the overflow boxes and from there back to the electrodes via the blow-in tubes.
  • An electrolysis system for the method according to the invention is designed, for example, for a maximum current I max of 6000 A, but it is only operated with a current of at most about 5400 A.
  • the system contains 36 copper cathodes with an active total area of 1: f of 77.1 m 2 and 38 stainless steel anodes with an active total area of 1 : f of 88.9 m2.
  • column 1 shows the electrolysis time, divided into hours
  • column 2 shows the decrease in the average cathodic current yield Ti - in percent as a function of the electrolysis time (column 1).
  • the electrolysis time can be determined from the experimental data in Table 1 according to Faraday's law on the basis of the following initial values to calculate. A duration t of 10 hours is calculated.
  • the electrolysis can be stopped after about ten to twelve hours if the current densities are reduced, which means that the electrolysis time is halved compared to the previous recovery electrolysis of copper, which uses a constant anodic current density .
  • the shorter electrolysis time also means that fewer EDTA decomposition products are formed.
  • Figure 6A shows the decrease in copper content in the copper plating bath during the first four hours of electrolysis.
  • 6B shows the decrease in the copper content of the bath from the fifth to the twelfth hour of the electrolysis, in each case with a constant anodic current density i + of 100 A / m 2 . If the anodic current density is reduced during the electrolysis, an even better average cathodic current yield and a further reduction in the electrolysis time are obtained.

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  • Chemical & Material Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electrolytic Production Of Metals (AREA)
  • Chemically Coating (AREA)
  • Electroplating And Plating Baths Therefor (AREA)

Claims (12)

1. Procédé pour la régénération d'un bain de dépôt chimique de cuivre ayant une teneur en un agent complexant, caractérisé par les stades opératoires suivants:
1. la prélèvement continu ou intermittent de la solution de bain contenant l'agent complexant, à partir du bain de dépôt chimique de cuivre;
2. l'abaissement de la teneur en cuivre de la solution de bain prélevée, à une valeur inférieure à 20 mg/I par électrolyse;
3. l'acidification de la solution de bain ainsi obtenue, pour la précipitation de l'agent complexant et sa récupération;
4. la dissolution de l'agent complexant récupéré, dans une solution alcaline d'un électrolyte et
5. le recyclage de la solution dans le bain de dépôt chimique de cuivre.
2. Procédé pour la régénération d'un bain de dépôt chimique de cuivre selon la revendication 1, caractérisé en ce que l'agent complexant est l'acide éthylènediaminetétra-acétique, le tartrate de potassium- sodium, l'éthylènediaminetétramine, la triéthanolamine ou la diéthanolamine.
3. Procédé selon la revendication 2, caractérisé en ce que l'agent complexant est l'acide éthylènediaminetétra-acétique.
4. Procédé selon la revendication 1, caractérisé en ce que l'on effectue l'électrolyse pour l'abaissement de la teneur en cuivre du bain sous circulation interne élevée.
5. Procédé selon la revendication 4, caractérisé en ce que l'on effectue l'électrolyse sous une circulation de bain d'environ 10 à 50 volumes/h.
6. Procédé selon la revendication 5, caractérisé en ce que l'on effectue l'électrolyse sous une circulation de bain de 20 volumes/h.
7. Procédé selon la revendication 1, caractérisé en ce que l'on maintient la valeur du pH constante pendant l'électrolyse.
8. Procédé selon la revendication 1, caractérisé en ce que, pendant l'électrolyse, on ne dépasse pas une densité de courant anodique i+ de 100 A/m2.
9. Procédé selon la revendication 1, caractérisé en ce que l'on abaisse la densité de courant anodique pendant l'électrolyse de manière correspondante à la courbe caractéristique d'électrolyse ou par degrés.
10. Procédé selon les revendications 1 à 3, caractérisé en ce qu'après l'élimination des ions cuivre, on précipite l'acide éthylènediaminetétra-acétique par acidification de la solution de bain à une valeur de pH inférieure à 2,0.
11. Procédé selon la revendication 10, caractérisé en ce que l'on purifie le EDTA précipité, par dissolution dans de la lessive de soude caustique et reprécipitation avec H2S04.
12. Procédé selon une ou plusieurs de revendications 1 à 11, caractérisé en ce que l'on dissout le ED-TA purifié, dans de la lessive de soude caustique et on l'envoie directement dans le bain de dépôt chimique de cuivre ou que l'on prépare un prémélange avec une solution de sulfate de cuivre et on envoie celui-ci dans le bain de dépôt chimique de cuivre.
EP86105002A 1986-04-11 1986-04-11 Procédé et appareillage pour la régénération d'un bain de dépôt chimique de cuivre Expired - Lifetime EP0240589B1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE8686105002T DE3668914D1 (de) 1986-04-11 1986-04-11 Verfahren zur regenerierung eines stromlosen verkupferungsbades und vorrichtung zur durchfuehrung desselben.
EP86105002A EP0240589B1 (fr) 1986-04-11 1986-04-11 Procédé et appareillage pour la régénération d'un bain de dépôt chimique de cuivre
JP62035963A JPS62243776A (ja) 1986-04-11 1987-02-20 無電解銅メッキ浴の再生方法
US07/033,387 US4734175A (en) 1986-04-11 1987-04-02 Process for regenerating an electroless copper plating bath

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP86105002A EP0240589B1 (fr) 1986-04-11 1986-04-11 Procédé et appareillage pour la régénération d'un bain de dépôt chimique de cuivre

Publications (2)

Publication Number Publication Date
EP0240589A1 EP0240589A1 (fr) 1987-10-14
EP0240589B1 true EP0240589B1 (fr) 1990-02-07

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EP86105002A Expired - Lifetime EP0240589B1 (fr) 1986-04-11 1986-04-11 Procédé et appareillage pour la régénération d'un bain de dépôt chimique de cuivre

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US (1) US4734175A (fr)
EP (1) EP0240589B1 (fr)
JP (1) JPS62243776A (fr)
DE (1) DE3668914D1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3455709B2 (ja) * 1999-04-06 2003-10-14 株式会社大和化成研究所 めっき方法とそれに用いるめっき液前駆体
US6391209B1 (en) 1999-08-04 2002-05-21 Mykrolis Corporation Regeneration of plating baths
US6596148B1 (en) 1999-08-04 2003-07-22 Mykrolis Corporation Regeneration of plating baths and system therefore
JP2001107258A (ja) * 1999-10-06 2001-04-17 Hitachi Ltd 無電解銅めっき方法とめっき装置および多層配線基板
US6848457B2 (en) * 2000-05-08 2005-02-01 Tokyo Electron Limited Liquid treatment equipment, liquid treatment method, semiconductor device manufacturing method, and semiconductor device manufacturing equipment
US6942779B2 (en) * 2000-05-25 2005-09-13 Mykrolis Corporation Method and system for regenerating of plating baths
US6733679B2 (en) * 2001-11-06 2004-05-11 Intel Corporation Method of treating an electroless plating waste
NL2009052C2 (en) 2012-06-21 2013-12-24 Autarkis B V A container for pcm, a pcm unit, a pcm module comprising a series of pcm units, and a climate system comprising a pcm module.

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3844799A (en) * 1973-12-17 1974-10-29 Ibm Electroless copper plating
DE2721994A1 (de) * 1977-04-06 1978-10-12 Bbc Brown Boveri & Cie Verfahren zur aufarbeitung waessriger rueckstaende von metallisierungsbaedern
US4302319A (en) * 1978-08-16 1981-11-24 Katsyguri Ijybi Continuous electrolytic treatment of circulating washings in the plating process and an apparatus therefor
US4324629A (en) * 1979-06-19 1982-04-13 Hitachi, Ltd. Process for regenerating chemical copper plating solution
US4425205A (en) * 1982-03-13 1984-01-10 Kanto Kasei Co., Ltd. Process for regenerating electroless plating bath and a regenerating apparatus of electroless plating bath
GB2133806B (en) * 1983-01-20 1986-06-04 Electricity Council Regenerating solutions for etching copper
US4549946A (en) * 1984-05-09 1985-10-29 Electrochem International, Inc. Process and an electrodialytic cell for electrodialytically regenerating a spent electroless copper plating bath

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Publication number Publication date
JPS62243776A (ja) 1987-10-24
DE3668914D1 (de) 1990-03-15
EP0240589A1 (fr) 1987-10-14
US4734175A (en) 1988-03-29
JPH0236677B2 (fr) 1990-08-20

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