CN115334767A - Surface treatment method of rolled copper foil for non-adhesive copper-clad plate, copper foil for non-adhesive flexible copper-clad plate and application of copper foil - Google Patents

Surface treatment method of rolled copper foil for non-adhesive copper-clad plate, copper foil for non-adhesive flexible copper-clad plate and application of copper foil Download PDF

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CN115334767A
CN115334767A CN202211061581.0A CN202211061581A CN115334767A CN 115334767 A CN115334767 A CN 115334767A CN 202211061581 A CN202211061581 A CN 202211061581A CN 115334767 A CN115334767 A CN 115334767A
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copper foil
ions
oxidation
layer
treatment
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薛方忠
常保平
张冒奇
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Shandong Tianhe Rolled Copper Foil Co ltd
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Shandong Tianhe Rolled Copper Foil Co ltd
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • 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
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • C23C22/52—Treatment of copper or alloys based thereon
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/02—Etching
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/24—Reinforcing the conductive pattern
    • H05K3/244—Finish plating of conductors, especially of copper conductors, e.g. for pads or lands

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Mechanical Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Manufacturing Of Printed Wiring (AREA)
  • Laminated Bodies (AREA)

Abstract

The invention belongs to the technical field of rolled copper foil surfaces, and particularly relates to a rolled copper foil surface treatment method, a copper foil for a non-adhesive flexible copper-clad plate and application thereof. The surface treatment method of the rolled copper foil comprises the following steps: carrying out micro-roughening treatment on a rolled copper foil serving as a cathode in an electrolyte to obtain a micro-roughened layer, wherein the electrolyte is an acidic solution of copper ions and nickel ions; soaking the copper foil with the micro-roughened layer in an alloy liquid, and carrying out alloying treatment to obtain an alloyed layer; the alloy liquid comprises nickel ions; immersing the copper foil with the alloyed layer into an anti-oxidation solution for anti-oxidation treatment to obtain an anti-oxidation layer; the anti-oxidation solution comprises chromium ions, zinc ions and sodium sulfate; and spraying a coupling agent solution on the surface of the oxidation-proof layer. The two-layer flexible copper clad laminate prepared from the surface treated rolled copper foil has higher oxidation temperature resistance and peel strength, and the etched polyimide film has high transparency.

Description

Surface treatment method of rolled copper foil for non-adhesive copper-clad plate, copper foil for non-adhesive flexible copper-clad plate and application of copper foil
Technical Field
The invention belongs to the technical field of rolled copper foil surface treatment, and particularly relates to a rolled copper foil surface treatment method, a copper foil for a non-adhesive flexible copper-clad plate and application thereof.
Background
The Flexible Copper Clad Laminate (FCCL) is a thin sheet composite material that can be repeatedly bent and is formed by coating copper foil on an insulating substrate (polyimide film, polyester film or polynaphthalene film, etc.), and is a Flexible Printed Circuit Board (FPCB) made of the composite material, and is mainly used for computer peripheral equipment and displays, aircraft instruments, navigation positioning devices, petroleum exploration equipment, missile tracing instruments, artificial satellites, space shuttles and spacecrafts, police radio telephones, portable video cameras and digital cameras, medical electronic products, and bus bars of circuit boards. The traditional flexible copper clad laminate is classified according to the manufacturing process and the product structure, and can be divided into a three-layer flexible copper clad laminate (3-LayerFCCL, also known as a flexible copper clad laminate with glue) and a two-layer flexible copper clad laminate (2-LayerFCCL, also known as a flexible copper clad laminate without glue). The two-layer flexible copper clad laminate consists of a copper foil layer and a polyimide insulating medium layer, has higher heat resistance, higher dimensional stability and more excellent flexibility than the three-layer flexible copper clad laminate, and has wider application.
The non-adhesive copper clad laminate is a copper clad laminate which is directly bonded between a copper foil layer and an insulating base material without an adhesive layer, and the manufacturing process comprises the steps of directly laminating a copper foil and thermoplastic polyimide, and obtaining the copper clad laminate after complete high-temperature lamination, baking and curing reaction. The non-adhesive copper-clad substrate has extremely high requirements on copper foil, and has the following main characteristics: (1) the etched polyimide film has high transparency; (2) the coating has high-temperature oxidation resistance; and (3) high peel strength.
With the development of electronic products towards light weight, thinness, shortness, smallness and high integration, higher requirements are put forward on the high temperature resistance of the two-layer flexible copper clad laminate serving as the base material of the electronic products. The polyimide in the two-layer method flexible copper clad laminate has higher glass transition temperature, the melting point of the polyimide is higher than the decomposition temperature, and the polyimide has good high temperature resistance, and the high temperature resistance of the two-layer method flexible copper clad laminate depends on the rolled copper foil. How to prepare the high-temperature-resistant rolled copper foil is a technical problem which needs to be solved urgently.
Disclosure of Invention
In view of the above, the invention provides a copper foil surface treatment method, a copper foil for a non-adhesive copper-clad plate and an application thereof, and the treatment of the surface of the copper foil according to the surface treatment method provided by the invention can obviously improve the high temperature resistance of the copper foil; the copper foil after surface treatment is used for preparing a two-layer method flexible copper clad laminate, has higher oxidation temperature resistance and peel strength, and the etched polyimide film has high transparency.
In order to solve the technical problem, the invention provides a surface treatment method of a rolled copper foil, which comprises the following steps:
carrying out micro-roughening treatment in electrolyte by taking the rolled copper foil as a cathode to obtain a micro-roughened layer, wherein the electrolyte is an acidic solution of copper ions and nickel ions;
immersing the copper foil with the micro-roughened layer into an alloy liquid, and carrying out alloying treatment to obtain an alloyed layer; the alloy liquid comprises metal ions, and the metal ions comprise nickel ions;
immersing the copper foil with the alloying layer into an anti-oxidation solution for anti-oxidation treatment to obtain an anti-oxidation layer; the anti-oxidation solution comprises chromium ions, zinc ions and sodium sulfate;
and spraying a coupling agent solution on the surface of the oxidation-resistant layer.
Preferably, the micro-roughening treatment has a current density of 40 to 50A/dm 2 The micro-roughening treatment time is 3-5 s; the temperature of the micro-roughening treatment is 30-40 ℃.
Preferably, the mass concentration of copper ions in the electrolyte is 8-15 g/L, and the mass concentration of nickel ions in the electrolyte is 1-3 g/L; the mass concentration of the acid in the electrolyte is 100-120 g/L.
Preferably, the mass concentration of the metal ions in the alloy liquid is 1-15 g/L;
the temperature of the alloying treatment is 25-35 ℃, and the current density of the alloying treatment is 30-50A/dm 2 The time of the alloying treatment is 10 to 20 seconds.
Preferably, the alloy liquid also comprises alloy ions and a complexing agent; the alloy ions are provided by alloy metal salts, and the alloy metal salts comprise one or two of nickel salts, cobalt salts, copper salts, tungsten salts and molybdenum salts; the mass concentration of the alloy ions in the alloy liquid is 1-15 g/L;
the complexing agent is organic acid, and the mass concentration of the complexing agent in the alloy liquid is 30-50 g/L.
Preferably, the mass concentration of chromium ions in the anti-oxidation solution is 0.5-1 g/L, the mass concentration of zinc ions is 2-4 g/L, and the mass concentration of sodium sulfate is 15-20 g/L; the pH value of the anti-oxidation solution is 3-4;
the temperature of the anti-oxidation treatment is 20-30 ℃, and the current density of the anti-oxidation treatment is 2-5A/dm 2 The time of the anti-oxidation treatment is 5 to 10 seconds.
Preferably, the volume concentration of the coupling agent solution is 1-2%; the coupling agent solution is a silane coupling agent solution;
the spraying temperature is 25-35 ℃.
Preferably, the method further comprises, before the micro-roughening treatment: sequentially carrying out electrolytic degreasing treatment and acid pickling on the copper foil;
the current density of the electrolytic degreasing treatment is 20-50A/dm 2 The time of the electrolytic degreasing treatment is 10-15 s;
the electrolyte for electrolytic degreasing treatment is an alkaline solution, and the volume concentration of the alkaline solution is 10-50%.
The invention also provides the copper foil for the adhesive-free flexible copper-clad plate obtained by the surface treatment method of the rolled copper foil according to the technical scheme, wherein the copper foil for the adhesive-free flexible copper-clad plate comprises a copper foil, a micro-roughening layer, an alloying layer, an anti-oxidation layer and a coupling agent film layer which are sequentially stacked; the alloying layer contains nickel, and the oxidation-resistant layer contains chromium and zinc.
The invention also provides the application of the rolled copper foil for the non-adhesive flexible copper clad laminate in the two-layer method flexible copper clad laminate.
The invention provides a surface treatment method of a rolled copper foil, which comprises the following steps: carrying out micro-roughening treatment in electrolyte by using the rolled copper foil as a cathode to obtain a micro-roughened layer, wherein the electrolyte is an acidic solution of copper ions and nickel ions; immersing the copper foil with the micro-roughened layer into an alloy liquid, and carrying out alloying treatment to obtain an alloyed layer; the alloy liquid comprises metal ions, and the metal ions comprise nickel ions; immersing the copper foil with the alloying layer into an anti-oxidation solution for anti-oxidation treatment to obtain an anti-oxidation layer; the anti-oxidation solution comprises chromium ions, zinc ions and sodium sulfate; and spraying a coupling agent solution on the surface of the oxidation-proof layer. According to the invention, an alloy layer containing nickel is formed on the surface of the micro-roughened copper foil layer through alloying treatment, so that the corrosion resistance and the high temperature resistance of the copper foil are improved; an oxidation preventing layer containing chromium and zinc is formed on the surface of the alloying layer after the alloying treatment by the oxidation preventing treatment, so that the oxidation resistance, the corrosion resistance and the high temperature resistance of the copper foil are further improved. The rolled copper foil treated by the surface treatment method provided by the invention is used for preparing the two-layer flexible copper clad laminate, and the high temperature resistance of the two-layer flexible copper clad laminate can be obviously improved. The two-layer flexible copper clad laminate prepared by the copper foil treated by the surface treatment method has high peel strength, and the etched polyimide film has high transparency.
Detailed Description
The invention provides a surface treatment method of a rolled copper foil, which comprises the following steps:
carrying out micro-roughening treatment in electrolyte by taking the rolled copper foil as a cathode to obtain a micro-roughened layer, wherein the electrolyte is an acidic solution of copper ions and nickel ions;
immersing the copper foil with the micro-roughened layer into an alloy liquid, and carrying out alloying treatment to obtain an alloyed layer; the alloy liquid comprises metal ions, and the metal ions comprise nickel ions;
immersing the copper foil with the alloying layer into an anti-oxidation solution for anti-oxidation treatment to obtain an anti-oxidation layer; the anti-oxidation solution comprises chromium ions, zinc ions and sodium sulfate;
and spraying a coupling agent solution on the surface of the oxidation-proof layer.
The invention uses to roll copperThe foil is used as a cathode, and micro-roughening treatment is carried out in electrolyte, namely an acidic solution of copper ions and nickel ions, to obtain a micro-roughened layer. In the present invention, it is preferable that before the micro-roughening treatment, the method further comprises subjecting the rolled copper foil to electrolytic degreasing treatment and acid washing in this order. In the present invention, the electrolytic solution for electrolytic degreasing treatment is preferably an alkaline solution, and the alkaline solution preferably includes a potassium hydroxide solution, a sodium hydroxide solution, or a sodium carbonate solution. In the present invention, the volume concentration of the alkaline solution is preferably 10 to 50%, more preferably 20 to 40%, and most preferably 30 to 35%. In the present invention, the temperature of the degreasing treatment is preferably 50 to 60 ℃, and more preferably 55 to 58 ℃. In the present invention, the current density of the electrolytic degreasing treatment is preferably 20 to 50A/dm 2 More preferably 30 to 40A/dm 2 (ii) a The time for the electrolytic degreasing treatment is preferably 10 to 15 seconds, and more preferably 12 to 15 seconds.
The present invention is not particularly limited to the anode for electrolytic degreasing, and any electrode conventionally used in the art may be used.
The electrolytic degreasing treatment can remove oil stains on the surface of the copper foil, and is beneficial to the subsequent micro-roughening treatment.
In the present invention, the acid washing is preferably performed by immersing the rolled copper foil after the electrolytic degreasing treatment in an acid solution. In the present invention, the acid solution is preferably an aqueous sulfuric acid solution. In the present invention, the mass concentration of the acid solution is preferably 100 to 160g/L, and more preferably 120 to 150g/L. In the present invention, the temperature of the soaking is preferably 20 to 40 ℃, more preferably 25 to 35 ℃, and most preferably 30 to 32 ℃; the soaking time is preferably 5 to 10 seconds, more preferably 7 to 9 seconds.
According to the invention, impurities on the surface of the copper foil can be removed through acid washing, and the impurities are preferably copper oxide.
In the present invention, the acidic solution of copper ions and nickel ions is preferably obtained by mixing copper salt, nickel salt and acid; the copper salt preferably comprises copper sulfate or copper chloride, more preferably copper sulfate; the nickel salt preferably comprises nickel sulfate or nickel chloride, more preferably nickel sulfate; the acid is preferably sulfuric acid. The mixing method is not particularly limited as long as the mixing can be performed uniformly. In the present invention, the mass concentration of copper ions in the electrolyte is preferably 8 to 15g/L, more preferably 10 to 12g/L; the mass concentration of nickel ions in the electrolyte is preferably 1-3 g/L, and more preferably 1.5-2 g/L; the mass concentration of the acid in the electrolyte is preferably 100 to 120g/L, and more preferably 105 to 110g/L.
In the invention, the temperature of the micro-roughening treatment is preferably 30-40 ℃, and more preferably 33-35 ℃; the current density of the micro-roughening treatment is preferably 40-50A/dm 2 More preferably 45 to 48A/dm 2 (ii) a The micro-roughening treatment time is preferably 3 to 5 seconds, and more preferably 3.5 to 4 seconds.
The present invention does not specifically limit the anode for micro-roughening treatment, and any electrode that is conventional in the art may be used.
According to the invention, copper buds can be formed on the surface of the rolled copper foil through micro-roughening treatment, and the surface roughness of the rolled copper foil is improved, so that the peel strength of the two-layer method flexible copper clad laminate is improved. Meanwhile, the copper bud formed by the method has lower height, and is beneficial to improving the transparency of the two-layer method flexible copper clad laminate after etching.
After the micro-roughened layer is obtained, the copper foil with the micro-roughened layer is immersed in alloy liquid for alloying treatment, and the alloyed layer is obtained. In the invention, the alloy liquid comprises metal ions, and the metal ions comprise nickel ions; the nickel ions are preferably provided by a nickel salt, which preferably comprises nickel sulphate or nickel chloride, more preferably nickel chloride. In the present invention, the mass concentration of the nickel ions in the alloy liquid is preferably 2 to 15g/L, and more preferably 5 to 10g/L. In the invention, the alloy liquid also preferably comprises alloy ions and a complexing agent; the alloy ions are preferably provided by alloy metal salts, which preferably include one or two of cobalt salts, copper salts, tungsten salts and molybdenum salts, and more preferably two of cobalt salts, copper salts, tungsten salts and molybdenum salts; the cobalt salt preferably comprises cobalt sulfate, cobalt chloride, more preferably cobalt sulfate; the copper salt preferably comprises copper sulfate or copper chloride, more preferably copper sulfate; the tungsten salt is preferably sodium tungstate; the molybdenum salt preferably comprises sodium molybdate or ammonium molybdate, more preferably sodium molybdate. In the present invention, the mass concentration of the metal ions in the alloy liquid is preferably 1 to 15g/L, more preferably 5 to 10g/L, and most preferably 6 to 8g/L. In the embodiment of the invention, the alloy metal salt is cobalt sulfate and sodium molybdate or copper sulfate and sodium tungstate or copper sulfate and cobalt sulfate or copper sulfate and sodium molybdate.
In the present invention, the complexing agent is preferably an organic acid, and the organic acid preferably includes ethylenediaminetetraacetic acid, glycine, or citric acid, and more preferably glycine or citric acid. In the present invention, the mass concentration of the complexing agent in the alloy liquid is preferably 30 to 50g/L, and more preferably 35 to 40g/L. In the invention, the complexing agent can promote nickel ions and alloy ions to codeposit on the cathode, so that the metal deposition potentials of the nickel ions and the alloy ions are close to each other, the codeposition is realized, and a multi-element alloy layer is formed after micro-roughening during electroplating.
In the present invention, the temperature of the alloying treatment is preferably 25 to 35 ℃, more preferably 25 to 30 ℃. In the present invention, the current density of the alloying treatment is preferably 30 to 50A/dm 2 More preferably 35 to 40A/dm 2 (ii) a The time for the alloying treatment is preferably 10 to 20 seconds, and more preferably 15 to 18 seconds.
The anode for alloying treatment in the present invention is not particularly limited, and an electrode conventionally used in the art may be used.
According to the invention, the alloy layer containing nickel is electroplated on the surface of the copper bud through alloying treatment, so that the corrosion resistance and high temperature resistance of the copper foil can be improved, and the requirement of continuous high-temperature roller pressing or laminating pressing mode of the adhesive-free flexible copper-clad plate on the high temperature resistance of the copper foil can be met.
After obtaining the alloyed layer, the copper foil with the alloyed layer is immersed into an anti-oxidation solution for anti-oxidation treatment to obtain the anti-oxidation layer. In the present invention, the oxidation preventing solution includes chromium ions, zinc ions, and sodium sulfate. In the present invention, the chromium ions are preferably provided by chromium trioxide; the zinc ion is preferably provided by a zinc salt, preferably including zinc sulphate or zinc chloride, more preferably zinc sulphate. In the invention, the mass concentration of the chromium ions in the anti-oxidation solution is preferably 0.5-1 g/L, and more preferably 0.6-0.8 g/L; the mass concentration of zinc ions in the anti-oxidation solution is preferably 2-4 g/L, and more preferably 2-3 g/L; the mass concentration of the sodium sulfate in the anti-oxidation solution is preferably 15-20 g/L, and more preferably 16-18 g/L; the pH value of the anti-oxidation solution is preferably 3-4.
In the present invention, the temperature of the oxidation preventing treatment is preferably 20 to 30 ℃, more preferably 23 to 25 ℃; the current density of the oxidation preventing treatment is preferably 2 to 5A/dm 2 More preferably 3 to 4A/dm 2 (ii) a The time for the oxidation preventing treatment is preferably 5 to 10 seconds, and more preferably 6 to 8 seconds.
The anode for the oxidation preventing treatment is not particularly limited, and an electrode which is conventional in the art can be used.
According to the invention, an anti-oxidation layer is electroplated on the surface of the alloying layer through anti-oxidation treatment, and zinc and chromium in the anti-oxidation layer can provide high temperature resistance, oxidation resistance and corrosion resistance of the copper foil.
After the anti-oxidation layer is obtained, the surface of the anti-oxidation layer is sprayed with a coupling agent solution. In the present invention, the coupling agent solution is preferably a silane coupling agent solution, and the silane coupling agent in the silane coupling agent solution preferably includes a ureido silane coupling agent, an ammonia silane coupling agent, or a methacryl silane coupling agent, and more preferably a ureido silane coupling agent or an ammonia silane coupling agent. In the present invention, the ureido-based silane coupling agent preferably includes a 3-ureidopropyltriethoxysilane coupling agent; the amino silane coupling agent preferably includes a 3-aminopropyltrimethoxysilane coupling agent or a 3-aminopropyltriethoxysilane coupling agent, and more preferably a 3-aminopropyltrimethoxysilane coupling agent. In the present invention, the volume concentration of the coupling agent solution is preferably 1 to 2%, more preferably 1.3 to 1.5%.
In the present invention, the temperature of the spraying is preferably 25 to 35 ℃, more preferably 28 to 30 ℃.
In the present invention, the spraying preferably further includes drying. In the present invention, the drying temperature is preferably 110 to 150 ℃, more preferably 120 to 130 ℃; the drying time is preferably 2 to 6s, more preferably 3 to 5s.
The invention has the advantages of low copper bud height, high oxidation temperature resistance, high peeling strength and high transparency of the etched polyimide film by micro-roughening treatment, alloying treatment and anti-oxidation treatment. The rolled copper foil after surface treatment has the properties of surface roughness, flexibility, high corrosion resistance and the like which can meet the requirements of a flexible printed circuit board.
The surface treatment method provided by the invention has the advantages of simple operation steps, strong continuity and low operation cost.
The invention also provides the copper foil for the adhesive-free flexible copper-clad plate, which is obtained by the copper foil surface treatment method according to the technical scheme, wherein the copper foil for the adhesive-free flexible copper-clad plate comprises a copper foil, a micro-roughening layer, an alloying layer, an anti-oxidation layer and a coupling agent film layer which are sequentially laminated; the alloying layer contains nickel, and the oxidation-resistant layer contains chromium and zinc. In the present invention, the height of the copper bud in the micro-roughened layer is preferably 500nm or less.
The invention also provides the application of the rolled copper foil for the non-adhesive flexible copper clad laminate in the two-layer method flexible copper clad laminate. In the invention, the high-temperature oxidation resistance of the two-layer method flexible copper clad laminate prepared by the copper foil for the adhesive-free flexible copper clad laminate is preferably more than 350 ℃ multiplied by 1min. In the invention, the two-layer method flexible copper clad laminate has good precision of optical positioning when etching lines, is not easy to scatter, and can be used for manufacturing fine patterns.
In order to further illustrate the present invention, the following technical solutions provided by the present invention are described in detail with reference to the examples, but they should not be construed as limiting the scope of the present invention.
Example 1
(1) Electrolytic degreasing treatment: immersing the rolled copper foil in a treatment tank containing a 30% by volume sodium hydroxide solution, using the rolled copper foil as a cathode, at a temperature of 55 ℃ and a current density of 30A/dm 2 Performing electrolytic degreasing for 15s under the condition of (1);
(2) Acid washing: soaking the rolled copper foil treated in the step (1) in a treatment tank filled with a sulfuric acid solution with the temperature of 30 ℃ and the mass concentration of 120g/L for 7s;
(3) Micro-roughening treatment: immersing the rolled copper foil treated in the step (2) into a micro-roughening tank filled with electrolyte for micro-roughening treatment; the electrolyte is a mixed solution of copper sulfate, nickel sulfate and sulfuric acid, wherein the mass concentration of copper ions is 8g/L, the mass concentration of nickel ions is 2g/L, and the mass concentration of sulfuric acid is 110g/L; the rolled copper foil treated in the step (2) is used as a cathode, and the temperature is 35 ℃, and the current density is 50A/dm 2 Performing micro-roughening treatment for 4s under the condition to obtain a micro-roughened layer;
(4) Alloying treatment: immersing the copper foil containing the micro-coarsening layer into an alloy liquid tank for alloying treatment; the alloy liquid is a mixed liquid of cobalt sulfate, sodium molybdate, nickel sulfate and glycine, wherein the mass concentration of cobalt ions is 5g/L, the mass concentration of molybdenum ions is 1g/L, the mass concentration of nickel ions is 10g/L, and the mass concentration of glycine is 30g/L; at a temperature of 25 ℃ and a current density of 30A/dm 2 Electroplating for 15s under the condition to obtain an alloyed copper foil;
(5) And (3) oxidation prevention treatment: immersing the copper foil containing the alloying layer into an anti-oxidation tank filled with an anti-oxidation solution for anti-oxidation treatment; the anti-oxidation solution is a mixed solution of chromium trioxide, zinc sulfate and sodium sulfate, wherein the mass concentration of chromium ions is 1g/L, the mass concentration of zinc ions is 3g/L, the mass concentration of sodium sulfate is 15g/L, and the pH value of the anti-oxidation solution is 3; at a temperature of 30 ℃ and a current density of 5A/dm 2 Carrying out anti-oxidation treatment for 9s under the condition of (1) to obtain an anti-oxidation layer;
(6) And spraying 3-aminopropyl trimethoxysilane coupling agent with the temperature of 30 ℃ and the volume concentration of 1% on the surface of the anti-oxidation copper layer, and drying at 120 ℃ for 4s to obtain the copper foil for the non-adhesive flexible copper clad laminate.
Example 2
The surface treatment was performed on the rolled copper foil in accordance with the method of example 1 except that the micro-roughening-treated electrolyte had a mass concentration of copper ions of 10g/L and a mass concentration of nickel ions of 3g/L; the current density of micro-roughening treatment is 40A/dm 2 The time is 5s;
the alloy liquid is copper sulfate and tungstenThe mixed solution of sodium, nickel sulfate and ethylenediamine tetraacetic acid, wherein the mass concentration of copper ions is 4g/L, the mass concentration of tungsten ions is 1g/L, the mass concentration of nickel ions is 10g/L, and the mass concentration of ethylenediamine tetraacetic acid is 30g/L; the current density of the alloying treatment is 35A/dm 2 For 15s;
the mass concentration of chromium ions in the anti-oxidation solution is 0.5g/L, the mass concentration of zinc ions is 4g/L, the mass concentration of sodium sulfate is 20g/L, and the pH value of the anti-oxidation solution is 3; the current density of the oxidation-resistant treatment is 4A/dm 2 The time is 6s.
Example 3
The surface treatment was performed on the rolled copper foil in accordance with the method of example 1 except that the micro-roughening-treated electrolyte had a mass concentration of copper ions of 15g/L and a mass concentration of nickel ions of 2g/L; the current density of the micro-roughening treatment is 45A/dm 2 The time is 3s;
the alloy liquid is a mixed liquid of copper sulfate, cobalt sulfate, nickel sulfate and citric acid, wherein the mass concentration of copper ions is 4g/L, the mass concentration of cobalt ions is 2g/L, the mass concentration of nickel ions is 15g/L, and the mass concentration of citric acid is 30g/L; the current density of the alloying treatment is 30A/dm 2 The time is 20s;
the mass concentration of chromium ions in the anti-oxidation solution is 0.8g/L, the mass concentration of zinc ions is 3g/L, the mass concentration of sodium sulfate is 18g/L, and the pH value of the anti-oxidation solution is 4; the current density of the oxidation-resistant treatment is 3A/dm 2 And the time is 7s.
Comparative example 1
The surface treatment was performed on the rolled copper foil by the method of example 1 except that the mass concentration of copper ions in the electrolyte for the micro-roughening treatment was 10g/L and the mass concentration of nickel ions was 0.5g/L; the current density of micro-roughening treatment is 50A/dm 2 The time is 5s;
the alloy liquid is a mixed liquid of copper sulfate, sodium molybdate, nickel sulfate and citric acid, wherein the mass concentration of copper ions is 4g/L, the mass concentration of molybdenum ions is 2g/L, the mass concentration of nickel ions is 10g/L, and the mass concentration of citric acid is 40g/L; the current density of the alloying treatment is 40A/dm 2 For 20s;
the mass concentration of chromium ions in the anti-oxidation solution is 1g/L, the mass concentration of zinc ions is 4g/L, the mass concentration of sodium sulfate is 15g/L, and the pH value of the anti-oxidation solution is 3; the current density of the oxidation-resistant treatment is 4A/dm 2 The time is 6s.
Comparative example 2
The surface treatment was performed on the rolled copper foil in accordance with the method of example 1 except that the micro-roughening-treated electrolyte had a mass concentration of copper ions of 10g/L and a mass concentration of nickel ions of 2g/L; the current density of micro-roughening treatment is 45A/dm 2 The time is 5s;
the alloy liquid is a mixed liquid of copper sulfate, cobalt sulfate, nickel sulfate and ethylene diamine tetraacetic acid, wherein the mass concentration of copper ions is 4g/L, the mass concentration of cobalt ions is 2g/L, the mass concentration of nickel ions is 2g/L, and the mass concentration of ethylene diamine tetraacetic acid is 35g/L; the current density of the alloying treatment is 35A/dm 2 The time is 20s;
the mass concentration of chromium ions in the anti-oxidation solution is 1g/L, the mass concentration of zinc ions is 0.5g/L, the mass concentration of sodium sulfate is 15g/L, and the pH value of the anti-oxidation solution is 3; the current density of the oxidation preventing treatment is 4A/dm 2 And the time is 8s.
Comparative example 3
The rolled copper foil was subjected to electrolytic degreasing treatment and acid pickling in accordance with the method of example 1;
the copper foil after acid cleaning is subjected to roughening treatment, wherein the mass concentration of copper ions is 10g/L, the mass concentration of sulfuric acid is 115g/L, the temperature is 35 ℃, and the current density is 40A/dm 2 Coarsening for 5s to obtain a coarsened layer;
curing the copper foil containing the coarsened layer, wherein the mass concentration of copper ions is 40g/L, the mass concentration of sulfuric acid is 120g/L, the temperature is 40 ℃, and the current density is 15A/dm 2 Curing for 5s to obtain a cured layer;
alloying the copper foil containing the solidified layer to obtain an alloyed layer; the alloy liquid is a mixed liquid of cobalt sulfate, nickel sulfate and citric acid, wherein the mass concentration of cobalt ions is 4g/L, and the mass concentration of nickel isThe mass concentration of the ions is 4g/L, and the mass concentration of the citric acid is 20g/L; the current density of the alloying treatment is 18A/dm 2 For 15s;
carrying out barrier layer treatment on the copper foil containing the alloying layer to obtain a barrier layer; the mass concentration of zinc ions is 3g/L, the mass concentration of potassium pyrophosphate is 20g/L, and the pH value of the solution is 11; the current density is 3A/dm 2 The time is 8s;
carrying out anti-oxidation treatment on the copper foil containing the barrier layer, wherein the mass concentration of chromium ions in an anti-oxidation solution is 1g/L, and the pH value of the solution is 11; the current density of the oxidation-resistant treatment is 2A/dm 2 The time period was 8s.
Comparative example 4
The surface treatment was carried out on the rolled copper foil according to the method of comparative example 3, except that the alloy liquid was a mixed liquid of copper sulfate, nickel sulfate and citric acid, in which the mass concentration of copper ions was 6g/L, the mass concentration of nickel ions was 4g/L, and the mass concentration of citric acid was 30g/L; the current density of the alloying treatment is 18A/dm 2 The time period was 15s.
The roughness, peel strength, high temperature oxidation resistance of the rolled copper foils prepared in examples 1 to 3 and comparative examples 1 to 4 were measured according to the IPC-TM-650 printed board metal foil test method; the results of measuring the height of copper buds on the surface of the rolled copper foils prepared in examples 1 to 3 and comparative examples 1 to 4 by using a scanning electron microscope are shown in table 1.
The rolled copper foils prepared in examples 1 to 3 and comparative examples 1 to 4 were prepared into two-layer flexible copper clad laminates, and the light transmittance of the polyimide in the etched two-layer flexible copper clad laminates was measured, and the results are shown in table 1.
TABLE 1 Performance parameters of copper foils of examples 1 to 3 and comparative examples 1 to 4
Figure BDA0003826445260000111
According to table 1, it can be seen that the obtained rolled copper foil after copper-nickel micro-roughening, alloying treatment and zinc-chromium anti-oxidation treatment has a lower copper bud height, a higher oxidation temperature resistance, a high peel strength, a higher transparency after etching the polyimide film, and other properties such as surface roughness, bendability, high corrosion resistance and the like, which can satisfy the requirements of the flexible printed wiring board.
From the results of comparative example 1, it can be seen that the light transmittance of the etched polyimide film is affected by the concentration of nickel ions in the electrolyte subjected to the micro-roughening treatment, and the etched polyimide film has a high light transmittance only when the concentration of nickel ions in the electrolyte is limited within the range of 1 to 3 g/L.
From the results of comparative example 2, it can be seen that the zinc ion concentration in the oxidation preventing solution for oxidation preventing treatment affects the high temperature resistance of the copper foil, and the copper foil can have higher high temperature resistance only if the mass concentration of the zinc ion is limited to 2-4 g/L.
Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and other embodiments can be obtained without inventive step according to the embodiments, and all of the embodiments are included in the scope of the present invention.

Claims (10)

1. A surface treatment method of a rolled copper foil comprises the following steps:
carrying out micro-roughening treatment in electrolyte by using the rolled copper foil as a cathode to obtain a micro-roughened layer, wherein the electrolyte is an acidic solution of copper ions and nickel ions;
immersing the copper foil with the micro-roughened layer into an alloy liquid, and carrying out alloying treatment to obtain an alloyed layer; the alloy liquid comprises metal ions, and the metal ions comprise nickel ions;
immersing the copper foil with the alloyed layer into an anti-oxidation solution for anti-oxidation treatment to obtain an anti-oxidation layer; the anti-oxidation solution comprises chromium ions, zinc ions and sodium sulfate;
and spraying a coupling agent solution on the surface of the oxidation-proof layer.
2. The surface treatment method for rolled copper foil according to claim 1, wherein the micro-roughening treatment has a current density of 40 to E50A/dm 2 The micro-roughening treatment time is 3-5 s; the temperature of the micro-roughening treatment is 30-40 ℃.
3. The rolled copper foil surface treatment method according to claim 1 or 2, wherein the mass concentration of copper ions in the electrolyte is 8 to 15g/L, and the mass concentration of nickel ions in the electrolyte is 1 to 3g/L; the mass concentration of the acid in the electrolyte is 100-120 g/L.
4. The rolled copper foil surface treatment method according to claim 1, wherein the mass concentration of metal ions in the alloy liquid is 1 to 15g/L;
the temperature of the alloying treatment is 25-35 ℃, and the current density of the alloying treatment is 30-50A/dm 2 The time of the alloying treatment is 10 to 20 seconds.
5. The surface treatment method of a rolled copper foil according to claim 1 or 4, characterized in that the alloy liquid further comprises alloy ions and a complexing agent; the alloy ions are provided by alloy metal salts, and the alloy metal salts comprise one or two of nickel salts, cobalt salts, copper salts, tungsten salts and molybdenum salts; the mass concentration of the alloy ions in the alloy liquid is 1-15 g/L;
the complexing agent is organic acid, and the mass concentration of the complexing agent in the alloy liquid is 30-50 g/L.
6. The surface treatment method for a rolled copper foil according to claim 1, wherein the mass concentration of chromium ions in the oxidation preventing solution is 0.5 to 1g/L, the mass concentration of zinc ions is 2 to 4g/L, and the mass concentration of sodium sulfate is 15 to 20g/L; the pH value of the anti-oxidation solution is 3-4;
the temperature of the anti-oxidation treatment is 20-30 ℃, and the current density of the anti-oxidation treatment is 2-5A/dm 2 The time of the anti-oxidation treatment is 5 to 10 seconds.
7. The surface treatment method of a rolled copper foil according to claim 1, wherein the volume concentration of the coupling agent solution is 1 to 2%; the coupling agent solution is a silane coupling agent solution;
the spraying temperature is 25-35 ℃.
8. The method of surface treatment of rolled copper foil according to claim 1, further comprising, before the micro-roughening treatment: sequentially carrying out electrolytic degreasing treatment and acid pickling on the copper foil;
the current density of the electrolytic degreasing treatment is 20-50A/dm 2 The time of the electrolytic degreasing treatment is 10-15 s;
the electrolyte for the electrolytic degreasing treatment is an alkaline solution, and the volume concentration of the alkaline solution is 10-50%.
9. The copper foil for a non-adhesive flexible copper-clad laminate obtained by the surface treatment method for a rolled copper foil according to any one of claims 1 to 8, wherein the copper foil for a non-adhesive flexible copper-clad laminate comprises a copper foil, a micro-roughening layer, an alloying layer, an oxidation preventing layer and a coupling agent film layer, which are laminated in this order; the alloying layer contains nickel, and the oxidation-resistant layer contains chromium and zinc.
10. The use of the calendered copper foil for the non-adhesive flexible copper clad laminate according to claim 9 in a two-layer process flexible copper clad laminate.
CN202211061581.0A 2022-08-31 2022-08-31 Surface treatment method of rolled copper foil for non-adhesive copper-clad plate, copper foil for non-adhesive flexible copper-clad plate and application of copper foil Pending CN115334767A (en)

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