US3880685A - Process and apparatus for etching copper and copper alloys - Google Patents

Process and apparatus for etching copper and copper alloys Download PDF

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Publication number
US3880685A
US3880685A US874100A US87410069A US3880685A US 3880685 A US3880685 A US 3880685A US 874100 A US874100 A US 874100A US 87410069 A US87410069 A US 87410069A US 3880685 A US3880685 A US 3880685A
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United States
Prior art keywords
copper
etching
hydrochloric acid
hydrogen peroxide
etching solution
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Expired - Lifetime
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US874100A
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English (en)
Inventor
Alfred Rehm
Winfried Eggert
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HOELLMUELLER MASCHBAU H
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HOELLMUELLER MASCHBAU H
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Priority claimed from DE19681807414 external-priority patent/DE1807414C3/de
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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
    • 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
    • C23F1/08—Apparatus, e.g. for photomechanical printing surfaces
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S134/00—Cleaning and liquid contact with solids
    • Y10S134/902—Semiconductor wafer

Definitions

  • ABSTRACT Copper and copper alloys, in particular copper-coated laminates, are etched by immersing them in or spraying them with a solution of cupric chloride and regenerating the formed cuprous chloride during continuing operation by adding hydrogen peroxide and hydrochloric acid to the etching solution, the amount of the addition being controlled by measurements of the redox potential by means of a redox electrode and the control being adjusted to add predetermined amounts of the said two additives whenever the copper-l-ion concentration reaches a predetermined value, preferably 0.4 g/l so as to maintain a constant etching speed.
  • the invention concerns a process for etching printed circuit boards in immersion and spray apparatus.
  • etching conductor plates e.g., printed circuits.
  • Known etching agents are aqueous solutions of ferric chloride (FeCl ammonium persulphate (NH S sodium chlorate and hydrochloric acid (NaClO HCl), sodium chlorite (NaClO hydrogen peroxide and sulfuric acid (H 0 H 80 and cupric chloride (CuCl with various regenerating agents such as air and oxygen.
  • Immersion or spray apparatus is used for etching, the latter, in particular, in the form of a continuous process operation particularly suitable for manufacture of conductive sheets on a conveyor belt.
  • An economical conveyor belt-type manufacture is conditional on maximum and constant throughput speed.
  • initial etching time is about l minute, but even when ferric chloride is used as the etching agent the initially high etching rate goes steadily down with rising copper contents and, in spray apparatus, etching times become uneconomical at copper contents of about 50 g resulting in low throughput rates.
  • a method of etching conductive plates of which the surface is formed by copper or a copper alloy comprising the steps of applying an etching solution of copper-II-chloride to the plate by immersion or spraying and regenerating the formed copper-l-chloride in the etching solution by adding hydrogen peroxide and hydrochloric acid to the solution during continuing operation, the amount of the addition being controlled by a continuous measurement of the redox potential of the etching solution by aredox electrode and the said control being adjusted to add predetermined amounts of hydrogen peroxide and hydrochloric acid whenever the copper-I-ion concentration reaches a predetermined value, so as to maintain a constant etching speed.
  • the invention also embraces an apparatus for carrying out the method just defined, comprising a tank for holding the etching solution, means for applying the solution to the copper or copper alloy surface, a redox electrode immersed in said tank for measuring the redox potential, at least one supply vessel for holding a regenerating liquid, a conduit between said vessel and said tank, valve means for opening and closing said conduit and passing liquid from said supply vessel to said tank, and control means for operatively connect ing said valve means with said redox electrode.
  • FIG. la is a graph plotting the Cu ion concentration of the etching solution against the redox potential iden tified as u;
  • FIG. lb is a partial enlarged view of the encircled portion of FIG. In;
  • FIG. 10 is a graph plotting the etching velocity v against the redox potential.
  • FIG. 2 is a diagrammatic view of the apparatus of the invention.
  • the process of the invention permits to shorten the mean etching time obtainable with iron chloride by a substantial amount, that is by about 40%. This is of course of great significance for the economies of the operation.
  • the dimensions of the conduits passing the regenerating liquid or liquids from the supply vessel or vessels to the tank holding the etching solution should be dimensioned so as to comply with the optimum amount-ratio of the regenerating chemicals.
  • valves which control the addition of regenerating liquids are arranged to be actuated in succession so that a small excess of hydrochloric acid may thus be supplied. This will then definitely avoid the decomposition of the hydrogen peroxide into hydrogen and oxygen.
  • copper-I-chloride when the etching is effected by using copper-II-chloride, copper-I-chloride will be formed according to the equation Cu CuCl 2 CuCl.
  • the absolute value of the copper content does not have to be particularly constant in order to obtain a high etching speed. Rather, it may vary between 80 g Cu/l and I30 g Cu/l. It is rather important to maintain the Cu-I-chloride amount which is being formed during the etching operation at a low value, for instance below 2 g/l, and to reoxidize it as fast as possible to copper-Il-chloride.
  • the potential of the electrode will be positive when the concentration of the higher oxidation stage rises and it will reach the maximum value when the Cu ion concentration is zero. With increasing Cu, ion content. the potential of the solution changes. This change will be comparatively stronger in the area of small Cu ion concentration (0 to 4 g/l) than with higher increases in the Cu ion as is illustrated by the curves in FIG. 1a and FIG. lb.
  • FIG. 1a illustrates qualitatively the interrelation between the etching velocity v and the redox potential u.
  • the redox potential u as will be seen, at 530 mV which occurs at a Cu* ion concentration of less than 0.4 g/l (see FIG. 1b) will afford an optimally high and almost constant etching speed. It is therefore preferred to practice the invention by maintaining this limit value during the regeneration of the etching agent.
  • the apparatus 1 may for instance be used to process conductive plates 2 which consist of a copper-coated laminate.
  • the conductive plates are passed by means of a conveyor belt 3 under the spray nozzles 4.
  • the hydrogen peroxide and hydrochloric acid are fed from the supply vessels 8 and 9 through magnet valves 10 and 11 and are furthermore pumped by pumps 12 and 13 into the etching solution in tank 5.
  • the magnet valves 10, l l and the pumps l2, 13 are controlled by the potential as determined through the redox electrode 14 and the control measuring device 15.
  • the control device comprises. in a preferred form, an amplifier, a measuring device and a recording device which, through amplification, indicate or record the potential differences.
  • the measuring device is provided with two adjustable sensors which cooperate with the hand of the measuring device.
  • the sensors and the hand of the measuring device are designed to generate a signal whenever the hand in response to a change of potential in the etching solution moves from the area of the higher potential with a gradually increasing Cu ion concentration into the area of a lower potential and in so moving passes the sensors and causes a response thereby.
  • the two sensors of the control device in order to attain a constant high etching speed, are adjusted to prevent exceeding a potential difference of about mV and thus to maintain the Cu ion content below 2 g/l.
  • the two sensors are also spaced from each other so that the first valve which adjusts the hydrochloric acid flow from the vessel 9 will open earlier than the second valve which controls the H 0 flow. Conversely, when the hand moves in the other direction, the hydrochloric acid valve will be closed at a definite time interval prior to the closing of the H 0 valve. This type of adjustment will assure that there is always a small HCl excess in the solution.
  • a particular advantage of the process of the invention is that the regenerating liquids can be supplied during the etching operation and that used'up etching solution can be withdrawn likewise during the operation. Thus, an interruption of the process. which heretofore has always been necessary. is avoided.
  • the spent etching solution also has a high re-use value since it consists of a hydrochloric acid-containing Cu-Il-chloride solution without addition of other salts, and can therefore be used in the manufacture of various kinds of copper compounds.
  • the material treated in this example were laminates with a facing of pure copper.
  • the solution in the tank at the commencement of the operation comprised 100-] 30 g copper Il-chloride per liter and a concentration of hydrochloric acid.
  • the solution was sprayed onto the plates at a temperature of 4050C which developed during the reaction.
  • the Redoxelectrode by means of the control device opened the valve of the supply vessel holding HCl and at the same time actuated the pump to feed HCl into the main tank.
  • the delayed action valve and pump of the supply vessel holding H 0 opened shortly thereafter.
  • a method for continuously etching copper conductive plates which comprises contacting the copper conductive plate to be etched with an etching solution of cupric chloride (copper (ll) chloride) and regenerating the etching solution containing cuprous chloride (copper (l) chloride) formed in the etching by reaction between said copper conductive plate and said etching solution by introducing hydrogen peroxide and hydrochloric acid into said etching solution, the amounts of hydrogen peroxide and hydrochloric acid introduced being regulated by continuously measuring the redox potential of said etching solution by means of a redox electrode and automatically introducing said hydrogen peroxide and hydrochloric acid whenever the cuprous ion (Cu(l) concentration in said etching solution exceeds 4 g/l in an amount at least sufficient to reduce said cuprous ion (Cu(l) concentration below said value whereby the cuprous ion concentration is continuously maintained below said value and a constant etching speed is maintained.

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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)
  • Manufacturing Of Printed Circuit Boards (AREA)
US874100A 1968-11-07 1969-11-05 Process and apparatus for etching copper and copper alloys Expired - Lifetime US3880685A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681807414 DE1807414C3 (de) 1968-11-07 Verfahren zum Ätzen von Kupfer und Kupferlegierungen, insbesondere von kupferkaschierten Schichtpreßstoffen

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US3880685A true US3880685A (en) 1975-04-29

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US874100A Expired - Lifetime US3880685A (en) 1968-11-07 1969-11-05 Process and apparatus for etching copper and copper alloys

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US (1) US3880685A (es)
JP (1) JPS5013223B1 (es)
AT (1) AT293812B (es)
BE (1) BE740609A (es)
CH (1) CH505213A (es)
ES (1) ES372831A1 (es)
FR (1) FR2022757A1 (es)
GB (1) GB1244415A (es)
LU (1) LU59712A1 (es)
NL (1) NL167477C (es)

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3951711A (en) * 1974-10-24 1976-04-20 General Dynamics Corporation System for maintaining uniform copper etching efficiency
US3962005A (en) * 1975-06-30 1976-06-08 Zenith Radio Corporation Method for etching shadow mask and regenerating etchant
US3964956A (en) * 1974-10-24 1976-06-22 General Dynamics Corporation System for maintaining uniform copper etching efficiency
DE2822032A1 (de) * 1977-12-30 1979-07-12 Chemcut Corp Vorrichtung und verfahren zur ionenregulierung von fluessigkeiten
DE3035864A1 (de) * 1980-09-23 1982-05-06 Siemens AG, 1000 Berlin und 8000 München Vorrichtung zur regenerierung salzsaurer kupferchlorid-aetzloesungen
US4696717A (en) * 1984-10-19 1987-09-29 International Business Machines Corporation Process for automatically regenerating copper chloride etch solutions
US4741798A (en) * 1985-11-11 1988-05-03 Hans Hollmuller Maschinenbau Gmbh & Co Installation for etching material
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
US5246023A (en) * 1990-04-24 1993-09-21 Electronic Controls Design, Inc. Method and apparatus to clean and cleanliness test printed circuit boards
US5259979A (en) * 1993-01-13 1993-11-09 Oliver Sales Company Process for regeneration of cleaning compounds
US5534078A (en) * 1994-01-27 1996-07-09 Breunsbach; Rex Method for cleaning electronic assemblies
US5671760A (en) * 1993-12-29 1997-09-30 Hirama Rika Kenkyujo Ltd. Apparatus for controlling resist stripping solution
US5722441A (en) * 1993-02-22 1998-03-03 Tokyo Electron Limited Electronic device process apparatus
US5746233A (en) * 1996-01-17 1998-05-05 Mitsubishi Denki Kabushiki Kaisha Washing apparatus and method therefor
US5896874A (en) * 1996-07-02 1999-04-27 Hirama Rika Kenkyujo Ltd. Apparatus for controlling resist stripping solution
US20030111098A1 (en) * 2001-12-18 2003-06-19 Kim Tae Woon Apparatus for stripping photoresist and method thereof
US6746547B2 (en) 2002-03-05 2004-06-08 Rd Chemical Company Methods and compositions for oxide production on copper
WO2009008801A1 (en) * 2007-07-11 2009-01-15 Sigma Engineering Ab A method for etching copper and recovery of the spent etching solution
US20100059084A1 (en) * 2008-09-10 2010-03-11 Austin American Technology Corporation Cleaning and testing ionic cleanliness of electronic assemblies
CN109811343A (zh) * 2019-03-19 2019-05-28 惠州市瑞翔丰科技有限公司 不含氨氮的环保蚀刻液及蚀刻方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113046746B (zh) * 2021-03-12 2023-03-10 合肥颀材科技有限公司 一种cof卷带精准蚀刻管控方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2908557A (en) * 1957-01-07 1959-10-13 Rca Corp Method of etching copper
US2927871A (en) * 1956-03-26 1960-03-08 Bethlehem Steel Corp Control of pickling baths
US2977199A (en) * 1956-12-31 1961-03-28 Ind Rayon Corp Method for the continuous testing of flowing materials
US3000385A (en) * 1957-10-30 1961-09-19 Wean Engineering Co Inc Pickling apparatus
US3074277A (en) * 1958-03-20 1963-01-22 Inland Steel Co Method and apparatus for automatic control of acid concentration in pickling system
US3117954A (en) * 1954-08-26 1964-01-14 Hoechst Ag Continuous diazotization
US3312189A (en) * 1963-12-24 1967-04-04 Hooker Chemical Corp Automatic solution control system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3117954A (en) * 1954-08-26 1964-01-14 Hoechst Ag Continuous diazotization
US2927871A (en) * 1956-03-26 1960-03-08 Bethlehem Steel Corp Control of pickling baths
US2977199A (en) * 1956-12-31 1961-03-28 Ind Rayon Corp Method for the continuous testing of flowing materials
US2908557A (en) * 1957-01-07 1959-10-13 Rca Corp Method of etching copper
US3000385A (en) * 1957-10-30 1961-09-19 Wean Engineering Co Inc Pickling apparatus
US3074277A (en) * 1958-03-20 1963-01-22 Inland Steel Co Method and apparatus for automatic control of acid concentration in pickling system
US3312189A (en) * 1963-12-24 1967-04-04 Hooker Chemical Corp Automatic solution control system

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964956A (en) * 1974-10-24 1976-06-22 General Dynamics Corporation System for maintaining uniform copper etching efficiency
US3951711A (en) * 1974-10-24 1976-04-20 General Dynamics Corporation System for maintaining uniform copper etching efficiency
US3962005A (en) * 1975-06-30 1976-06-08 Zenith Radio Corporation Method for etching shadow mask and regenerating etchant
DE2822032A1 (de) * 1977-12-30 1979-07-12 Chemcut Corp Vorrichtung und verfahren zur ionenregulierung von fluessigkeiten
DE3035864A1 (de) * 1980-09-23 1982-05-06 Siemens AG, 1000 Berlin und 8000 München Vorrichtung zur regenerierung salzsaurer kupferchlorid-aetzloesungen
EP0178347B1 (de) * 1984-10-19 1988-09-07 Ibm Deutschland Gmbh Verfahren zum automatischen Regenerieren von Kupferchlorid-Ätzlösungen
US4696717A (en) * 1984-10-19 1987-09-29 International Business Machines Corporation Process for automatically regenerating copper chloride etch solutions
US4741798A (en) * 1985-11-11 1988-05-03 Hans Hollmuller Maschinenbau Gmbh & Co Installation for etching material
US5013395A (en) * 1987-08-28 1991-05-07 International Business Machines Corporation Continuous regeneration of acid solution
US5246023A (en) * 1990-04-24 1993-09-21 Electronic Controls Design, Inc. Method and apparatus to clean and cleanliness test printed circuit boards
US5227010A (en) * 1991-04-03 1993-07-13 International Business Machines Corporation Regeneration of ferric chloride etchants
US5259979A (en) * 1993-01-13 1993-11-09 Oliver Sales Company Process for regeneration of cleaning compounds
US5722441A (en) * 1993-02-22 1998-03-03 Tokyo Electron Limited Electronic device process apparatus
US5671760A (en) * 1993-12-29 1997-09-30 Hirama Rika Kenkyujo Ltd. Apparatus for controlling resist stripping solution
US5534078A (en) * 1994-01-27 1996-07-09 Breunsbach; Rex Method for cleaning electronic assemblies
US5746233A (en) * 1996-01-17 1998-05-05 Mitsubishi Denki Kabushiki Kaisha Washing apparatus and method therefor
US5896874A (en) * 1996-07-02 1999-04-27 Hirama Rika Kenkyujo Ltd. Apparatus for controlling resist stripping solution
US20030111098A1 (en) * 2001-12-18 2003-06-19 Kim Tae Woon Apparatus for stripping photoresist and method thereof
US7740709B2 (en) * 2001-12-18 2010-06-22 Lg Display Co., Ltd. Apparatus for stripping photoresist and method thereof
US6746547B2 (en) 2002-03-05 2004-06-08 Rd Chemical Company Methods and compositions for oxide production on copper
WO2009008801A1 (en) * 2007-07-11 2009-01-15 Sigma Engineering Ab A method for etching copper and recovery of the spent etching solution
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
US20100059084A1 (en) * 2008-09-10 2010-03-11 Austin American Technology Corporation Cleaning and testing ionic cleanliness of electronic assemblies
CN109811343A (zh) * 2019-03-19 2019-05-28 惠州市瑞翔丰科技有限公司 不含氨氮的环保蚀刻液及蚀刻方法

Also Published As

Publication number Publication date
ES372831A1 (es) 1971-11-01
FR2022757A1 (es) 1970-08-07
NL6916811A (es) 1970-05-11
NL167477B (nl) 1981-07-16
BE740609A (es) 1970-04-01
LU59712A1 (es) 1970-01-12
NL167477C (nl) 1981-12-16
GB1244415A (en) 1971-09-02
CH505213A (de) 1971-03-31
AT293812B (de) 1971-10-25
DE1807414B2 (de) 1971-03-18
JPS5013223B1 (es) 1975-05-17
DE1807414A1 (de) 1970-06-18

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