EP0178347B1 - Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen - Google Patents

Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen Download PDF

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Publication number
EP0178347B1
EP0178347B1 EP84112630A EP84112630A EP0178347B1 EP 0178347 B1 EP0178347 B1 EP 0178347B1 EP 84112630 A EP84112630 A EP 84112630A EP 84112630 A EP84112630 A EP 84112630A EP 0178347 B1 EP0178347 B1 EP 0178347B1
Authority
EP
European Patent Office
Prior art keywords
sodium chloride
hydrochloric acid
copper
regeneration unit
process according
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
Application number
EP84112630A
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German (de)
English (en)
French (fr)
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EP0178347A1 (de
Inventor
Werner Dieter 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 AT84112630T priority Critical patent/ATE37047T1/de
Priority to EP84112630A priority patent/EP0178347B1/de
Priority to DE8484112630T priority patent/DE3473891D1/de
Priority to JP60155294A priority patent/JPS6199683A/ja
Priority to US06/787,560 priority patent/US4696717A/en
Publication of EP0178347A1 publication Critical patent/EP0178347A1/de
Application granted granted Critical
Publication of EP0178347B1 publication Critical patent/EP0178347B1/de
Expired legal-status Critical Current

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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
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/46—Regeneration of etching compositions

Definitions

  • the invention relates to a method for the automatic regeneration of copper chloride etching solutions, in which the etchant is withdrawn from the etching chamber and regenerated in a separate regeneration unit with hydrogen peroxide and hydrochloric acid, diluted with water and then fed back to the etching chamber.
  • printed circuits can be produced by etching copper or aluminum alloy clad insulating boards with a hydrochloric acid copper (II) chloride solution.
  • the copper (I) chloride formed during the etching of copper with copper (II) chloride according to the equation must be re-oxidized to copper (II) chloride during the regeneration phase by adding a suitable oxidizing agent.
  • oxidizing agents are either compressed air, which can be supplied through frits at the bottom of a standing container (DE-C 12 07 183), or chlorine gas (US-A 3 083 129 and DE-C 16 21 437), or sodium chlorate (DE -C 12 25 465), or hydrogen peroxide and hydrochloric acid (DE-C 18 07 414 and Z. Elektronik, 1969 issue 11, pages 335 and 336, «Modern etching processes for pressure circuits •) in question.
  • the aqueous solutions of hydrogen peroxide and hydrochloric acid are metered into the etching machine by measuring the redox potential.
  • metering takes place in accordance with DE-C 18 07 414 in such a way that the first valve regulating the hydrochloric acid inflow opens well before the second valve regulating the H 2 O 2 inflow and closes clearly after the H 2 0 2 valve is, which ensures that there is always an excess of HCI in the solution.
  • the etching solution has a 10% concentration of HCl, which corresponds to a concentration of 120 g / l HCl at 20 ° C.
  • H 2 0 2 is added to such a strongly acidic solution, it does not decompose.
  • the used etching solution can also be regenerated with oxygen-containing gas and the etched copper can be recovered by electrolysis.
  • the peroxide process has so far been the cheapest for reasons of cost and because of its high reaction rate and yield.
  • the device designed for this method is characterized by the connection of a Venturi tube on the pressure side of a pump between the inlet and outlet to and from the etching chamber and at least two suction connections and magnetic valves to storage containers for hydrogen peroxide or hydrochloric acid.
  • the device is operated in such a way that peroxide and hydrochloric acid are metered into the etchant one after the other.
  • DE-A 2 942 504 discloses a copper (II) chloride-containing etching solution for the etching of copper on printed circuit boards, which uses an alkali metal chloride, in particular potassium chloride, as complexing agent instead of hydrochloric acid.
  • an alkali metal chloride in particular potassium chloride
  • the etching solution can be regenerated in a simple manner by introducing air.
  • air oxidation requires filtering of the copper (II) hydroxide formed, from which it is dissolved by acid and subsequent Electrolysis copper can be obtained in metallic form. This process cannot be carried out in a closed circuit because the copper obtained in the form of copper hydroxide is difficult to filter from the etching solution.
  • the object of the invention is to provide a method for regenerating exhausted copper chloride etching solutions which can be carried out continuously and fully automatically and works practically with 100% efficiency.
  • the regeneration method according to the invention uses hydrogen peroxide and hydrochloric acid for the regeneration, the hydrochloric acid concentration in the etching solution being kept very low and the missing chloride ions being provided by adding sodium chloride and maintaining a constant sodium chloride concentration in the etching solution.
  • the object of the invention is achieved by a regeneration process, which is characterized in that in an oxidation reactor or static mixer, an amount of hydrogen peroxide corresponding to the copper (I) ion concentration to be regenerated is reacted with the stoechiometric amount of hydrochloric acid to form hypochlorous acid and immediately thereafter with the to be regenerated etching solution, which has a hydrochloric acid concentration below 20 ml / l 32% HCI and contains sodium chloride as a complexing agent.
  • the invention also includes a regeneration device for performing the automatic regeneration of copper chloride etching solutions.
  • etching and regeneration are carried out in separate devices, the etching solution being circulated between the two devices continuously and at high speed.
  • the volume of the regeneration tank is designed to be substantially larger than that of the etcher, so that several etchers can be connected to the same regeneration unit if necessary.
  • Etching with copper (II) chloride results from the equation: Cu + CuCl 2 ⁇ 2 CuCI copper (I) chloride, which is practically insoluble in the etching bath and through the formation of an inhibiting film on the surface of the copper to be etched even at a low concentration the etching speed of the etching solution slows down noticeably. It is therefore desirable to keep the amount of copper (I) chloride formed during the etching process as low as possible, or to quickly oxidize the copper (I) chloride again to copper (II) chloride.
  • the copper (I) chloride can indeed be kept in solution in the etching solutions by chloride ions in complex form, these being provided according to the prior art by contents of the etching solution of concentrated hydrochloric acid of greater than 200 ml / l.
  • a disadvantage of these strongly hydrochloric acid solutions is that the service life of the etching machines and regeneration units is reduced and the quality of the etched conductor path pattern is impaired by undercutting, which is no longer tolerable, especially with the conductor path widths of less than 100 ⁇ m desired today.
  • the hydrochloric acid content of the copper chloride etching solutions should therefore be reduced according to the invention to contents below about 30 ml HCl 32% / 1 and the missing chloride should be added in the form of sodium chloride.
  • This increases the etching rates of the etching solutions considerably more than the previously mentioned high hydrochloric acid contents.
  • the etching solution can also absorb significantly more Cu 1+ than would be the case with strongly hydrochloric acid solutions due to the strong binding of the monovalent copper in the form of the [CuCl 2 ] complex.
  • an etching solution with a sodium chloride content of about 3 mol / l can still be etched satisfactorily with a copper (1) content of about 20 g / l.
  • the copper (I) chloride in the oxidation reactor immediately after its formation according to the following reaction equation: practically oxidized to copper (II) chloride with 100% efficiency.
  • the water required to dilute the etching solution to the desired concentration is fed to the regeneration unit (FIG. 3) or the salt tank (FIG. 4) via a separate line.
  • FIG. 2 shows an oxidation reactor in which the reactions indicated in FIG. 1 take place.
  • the copper (I) chloride-containing etching solution flows through the central tube.
  • Hydrogen peroxide and hydrochloric acid are metered in via the lateral lines in such a way that they react to hypochlorous acid and water shortly before they meet the etching solution to be regenerated.
  • the etching solution as shown in the lower part of the oxidation reactor, two molecules of copper (I) chloride react with one molecule of the hypochlorous acid formed and one molecule of hydrochloric acid to form two molecules of copper (II) chloride and water. Water is metered in through the line drawn on the far right in order to constantly maintain the desired concentration of copper (II) ions in the etching solution.
  • a free fall is provided for the etching solution until it enters the regeneration unit 2. It is also advantageous to arrange an interruption between the reservoir 9 for H 2 0 2 and the oxidation reactor 12 (not shown).
  • a static mixer can also be used for the reaction of H 2 0 2 and Hcl and the oxidation of the copper (I) chloride with HCIO.
  • the Cu 2 + ion concentration of the etching solution can vary in the range from 80 to 170 g / l.
  • the highest etching rate that is desired for the production of fine conductors is achieved at a concentration of 95 g / l C U 2+ .
  • the concentration of the etching solution is then kept constant at ⁇ 1 g / l.
  • the 32% hydrochloric acid content can vary between 8 and 20 ml per liter of etching solution. It should be pointed out once again that etching solutions according to the prior art contain 200 ml / l and above of concentrated hydrochloric acid, due to the high content of the etching solution used according to the invention gene sodium chloride, as already stated, larger amounts of Cu 1+ complex can be kept in solution, so that copper (II) chloride etching solutions with a content of 20 g / I Cu 1+ are still etched satisfactorily can.
  • hydrogen peroxide and hydrochloric acid are used to regenerate the etching solutions described above when they are enriched in copper (I) chloride.
  • I copper
  • a consumption of 1.36 I 35% hydrogen peroxide, 3.1 I 32% HCI, 2.4 kg sodium chloride (salt basket principle) or 2.15 kg sodium chloride (salt tank principle) and 5.7 I water is calculated for the Regeneration of 1 kg copper.
  • a ratio of the addition of H 2 0 2 : H 2 0: HCl 1: 4.2: 2.3 results from the amounts given above.
  • FIGS. 3 and 4 show regeneration devices for carrying out the method according to the invention.
  • an etcher 1 is connected to a regeneration unit 2.
  • the storage containers 9, 10 and 11 are provided for hydrogen peroxide, hydrochloric acid and water.
  • the etching solution to be regenerated. is fed to the oxidation reactor 12.
  • lines extend from the storage containers 9.10 and 11 to the oxidation reactor 12.
  • a redox electrode (sensor) 4 controls the opening of the solenoid valve 6 via a regulator 5 depending on the measured potential, so that the precisely required amount of hydrogen peroxide flows to the oxidation reactor .
  • the solenoid valves 7 and 8 are also actuated via the controller 5, so that hydrochloric acid and water flow in calculated amounts from the metering tanks 10 and 11 to the oxidation reactor 12.
  • dosing pumps can also be used for dosing.
  • a salt basket 3a in which solid sodium chloride is always present, is arranged in the regeneration unit 2.
  • the etching solution flows through the measuring cell (sensor) 4 at a constant flow rate.
  • the pump 13 ensures that the regenerated etching solution is returned to the etching device.
  • Excessive etching solution which is constantly newly formed by the etching and regeneration process, flows via an overflow into the overflow container 14. The excess etching solution is sold to a copper smelter for the recovery of copper.
  • a closed salt tank 3b is provided in the regeneration unit 2 instead of the open salt basket. Water is then metered from the reservoir 11 not into the oxidation reactor 12, but directly into the salt tank 3b. From there, an overflow to the regeneration unit 2 is provided.
  • a redox electrode is used to control the addition of chemicals to the etching solution to be regenerated, ie to maintain the advantageous concentrations of the chemicals described above, with which the desired goal can be achieved with great accuracy.
  • the redox potential measured between. the half element Au, Cu 2+ / Cu + and a comparison electrode, e.g. B. a calome electrode. This potential is dependent on the concentration ratio (activity ratio) Cu 2+ : Cu + , but not pure redox potentials are measured, but a mixed potential, which also depends on the sodium chloride content of the etching solution and on the liquid flow V with which the etching solution flows through the sensor is.
  • the constant flow rate through the measuring cell is achieved in that a small amount of etching solution from the regeneration unit 2 circulates continuously in a secondary circuit through the measuring cell (sensor 4), which is preceded by a reducing valve and a flow meter (not shown).
  • the sodium chloride concentration is kept constant by working either with a solution saturated with sodium chloride or with a solution whose concentration is below the degree of saturation but is constant.
  • An etching solution saturated with sodium chloride is obtained by arranging a salt basket 3a in the regeneration unit 2, in which always solid Sodium chloride is present (Fig. 3).
  • the etching solution flowing through the salt basket absorbs about 4 mol / l sodium chloride up to its degree of saturation, which corresponds to 234 g / l sodium chloride.
  • a salt tank 3b is used to set and maintain a constant sodium chloride concentration, the content of which is separate from the regeneration unit 2.
  • Solid sodium chloride is located at the bottom of the closed salt tank 3b (FIG. 4).
  • the water from the storage container 11 is not metered directly into the regeneration unit as in the case of the salt basket principle (FIG. 3), but rather into the salt tank 3b.
  • Saturated saline solution then enters the regeneration unit 2 via an overflow (FIG. 4).
  • a constant sodium chloride concentration can also be set in the etching solution.
  • the redox potential is only dependent on the ratio Cu2 +: Cu + .
  • the potential difference is between 2 and 5 g / I Cu 1+ . B. always 26.5 mV. It is therefore favorable to regulate the bath composition in this area with the help of the redox potential. However, since the value of the potential difference of 26.5 mV shifts with the copper (II) ion concentration and the temperature, the temperature must be kept within narrow limits in order to precisely regulate the oxidation of Cu + to C U 2+ .
  • the potential difference is displayed on a measuring device via an amplifier and recorded with a recorder.
  • the measuring device is provided with a sensor, which is passed by the pointer of the measuring device in accordance with the potential difference in the etching solution.
  • a solenoid valve is opened or a metering pump is actuated in order to meter hydrogen peroxide from a storage container into the oxidation reactor above the regeneration system. Hydrochloric acid and water are added in calculated amounts.
  • the method according to the invention it is possible to regenerate copper chloride etching solutions that have been used up on an industrial scale.
  • hydrogen peroxide and hydrochloric acid are used in a known manner.
  • the etching solutions contain much less hydrochloric acid than previously known etching solutions.
  • hydrochloric acid is only added in the amount that is required stoichiometrically for conversion with hydrogen peroxide to hypochlorous acid.
  • the activity of the etching bath is significantly increased by adding sodium chloride.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • ing And Chemical Polishing (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)
EP84112630A 1984-10-19 1984-10-19 Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen Expired EP0178347B1 (de)

Priority Applications (5)

Application Number Priority Date Filing Date Title
AT84112630T ATE37047T1 (de) 1984-10-19 1984-10-19 Verfahren zum automatischen regenerieren von kupferchlorid-aetzloesungen.
EP84112630A EP0178347B1 (de) 1984-10-19 1984-10-19 Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen
DE8484112630T DE3473891D1 (en) 1984-10-19 1984-10-19 Process for automatically regenerating cupric chloride etching solutions
JP60155294A JPS6199683A (ja) 1984-10-19 1985-07-16 塩化銅エッチング溶液の再生方法
US06/787,560 US4696717A (en) 1984-10-19 1985-10-15 Process for automatically regenerating copper chloride etch solutions

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP84112630A EP0178347B1 (de) 1984-10-19 1984-10-19 Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen

Publications (2)

Publication Number Publication Date
EP0178347A1 EP0178347A1 (de) 1986-04-23
EP0178347B1 true EP0178347B1 (de) 1988-09-07

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ID=8192231

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EP84112630A Expired EP0178347B1 (de) 1984-10-19 1984-10-19 Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen

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US (1) US4696717A (enrdf_load_stackoverflow)
EP (1) EP0178347B1 (enrdf_load_stackoverflow)
JP (1) JPS6199683A (enrdf_load_stackoverflow)
AT (1) ATE37047T1 (enrdf_load_stackoverflow)
DE (1) DE3473891D1 (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19719659A1 (de) * 1997-05-09 1998-11-12 Eilenburger Elektrolyse & Umwelttechnik Gmbh Verfahren und Vorrichtung zur Kontrolle von Kupferbeizbädern
DE10300597A1 (de) * 2003-01-10 2004-07-22 Eilenburger Elektrolyse- Und Umwelttechnik Gmbh Verfahren und Vorrichtung zur vollständigen Regenerierung von Metallchlorid-Ätzlösungen für Kupferwerkstoffe

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5227010A (en) * 1991-04-03 1993-07-13 International Business Machines Corporation Regeneration of ferric chloride etchants
US5650249A (en) * 1992-11-18 1997-07-22 The Boeing Company Method for making precision radomes
US5468409A (en) * 1993-11-03 1995-11-21 The Boeing Company Copper etchant useful for making fine-line copper elements
US5560838A (en) * 1994-12-05 1996-10-01 Training `N` Technology, Inc. Process and apparatus for converting spent etchants
JP3597250B2 (ja) * 1995-03-31 2004-12-02 日本アクア株式会社 エッチング液の再生方法およびエッチング液再生装置
EP0854119A3 (en) * 1996-12-20 1998-11-18 Hoya Corporation Etchant and method for etching chalcogenide glass and optical member having smooth surface
RU2203346C2 (ru) * 2001-06-13 2003-04-27 Федеральное Государственное Унитарное Предприятие "Центральный Научно-Исследовательский Институт Конструкционных Материалов "Прометей" Аустенитная кремнистая сталь
KR20030006809A (ko) * 2001-07-16 2003-01-23 (주)오알켐 연속적인 작업과 공급이 가능토록 에칭작업액을재생시키는 조성물 및 그 공급방법
KR100416989B1 (ko) * 2001-07-16 2004-02-05 (주)오알켐 전산화 에칭액 자동 공급장치
US6616828B2 (en) * 2001-08-06 2003-09-09 Micron Technology, Inc. Recovery method for platinum plating bath
KR101014009B1 (ko) 2005-05-25 2011-02-22 강훈 현상 부식 박리 콘트롤러
SE531697C2 (sv) * 2007-07-11 2009-07-07 Sigma Engineering Ab Etsnings- och återvinningsförfarande
CN116200747B (zh) * 2023-05-06 2023-07-18 汕头市精工东捷制版有限公司 基于印刷设备版辊铜层的喷淋式高精细深度腐蚀工艺

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3880685A (en) * 1968-11-07 1975-04-29 Hoellmueller Maschbau H Process and apparatus for etching copper and copper alloys

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GB955000A (en) * 1961-04-13 1964-04-08 Marconi Co Ltd Improvements in or relating to copper etching solutions
US3306792A (en) * 1963-08-05 1967-02-28 Siemens Ag Continuously regenerating coppercontaining etching solutions
DE2156699C3 (de) * 1971-11-15 1975-07-03 Chemcut Corp., State College, Pa. (V.St.A.) Verfahren und Vorrichtung zum automatischen Regenerieren von KupferchloridÄtzmittellösungen
JPS5124537A (en) * 1974-08-26 1976-02-27 Hitachi Ltd Etsuchinguyokuno saiseihoho
JPS53103942A (en) * 1977-02-22 1978-09-09 Matsushita Electric Ind Co Ltd Method and apparatus for etching of copper and copper alloy
JPS55152180A (en) * 1979-05-14 1980-11-27 Dainippon Screen Mfg Co Ltd Method for regeneration of copper chloride etching solution
DE2942504A1 (de) * 1979-10-20 1981-04-30 Robert Bosch Gmbh, 7000 Stuttgart Aetzloesung zum aetzen von kupfer
DE3035864A1 (de) * 1980-09-23 1982-05-06 Siemens AG, 1000 Berlin und 8000 München Vorrichtung zur regenerierung salzsaurer kupferchlorid-aetzloesungen

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3880685A (en) * 1968-11-07 1975-04-29 Hoellmueller Maschbau H Process and apparatus for etching copper and copper alloys

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19719659A1 (de) * 1997-05-09 1998-11-12 Eilenburger Elektrolyse & Umwelttechnik Gmbh Verfahren und Vorrichtung zur Kontrolle von Kupferbeizbädern
DE10300597A1 (de) * 2003-01-10 2004-07-22 Eilenburger Elektrolyse- Und Umwelttechnik Gmbh Verfahren und Vorrichtung zur vollständigen Regenerierung von Metallchlorid-Ätzlösungen für Kupferwerkstoffe

Also Published As

Publication number Publication date
US4696717A (en) 1987-09-29
DE3473891D1 (en) 1988-10-13
ATE37047T1 (de) 1988-09-15
JPS6363633B2 (enrdf_load_stackoverflow) 1988-12-08
EP0178347A1 (de) 1986-04-23
JPS6199683A (ja) 1986-05-17

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