Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/56—Electroplating: Baths therefor from solutions of alloys
  • C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/38—Chromatising
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/34—Pretreatment of metallic surfaces to be electroplated
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/48—After-treatment of electroplated surfaces
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D9/00—Electrolytic coating other than with metals
  • C25D9/04—Electrolytic coating other than with metals with inorganic materials
  • C25D9/08—Electrolytic coating other than with metals with inorganic materials by cathodic processes
• • 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
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
  • H05K9/0073—Shielding materials
  • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
  • H05K9/0084—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single continuous metallic layer on an electrically insulating supporting structure, e.g. metal foil, film, plating coating, electro-deposition, vapour-deposition
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D7/00—Electroplating characterised by the article coated
  • C25D7/06—Wires; Strips; Foils
  • C25D7/0614—Strips or foils
• • 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
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/0213—Electrical arrangements not otherwise provided for
  • H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
  • H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
• • 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
  • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
  • H05K2201/03—Conductive materials
  • H05K2201/0332—Structure of the conductor
  • H05K2201/0335—Layered conductors or foils
  • H05K2201/0355—Metal foils
• • 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
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
  • H05K2203/0703—Plating
  • H05K2203/0723—Electroplating, e.g. finish plating
• • 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
  • H05K3/38—Improvement of the adhesion between the insulating substrate and the metal
  • H05K3/382—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal
  • H05K3/384—Improvement of the adhesion between the insulating substrate and the metal by special treatment of the metal by plating
• • 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
  • H05K9/00—Screening of apparatus or components against electric or magnetic fields
  • H05K9/0073—Shielding materials
  • H05K9/0094—Shielding materials being light-transmitting, e.g. transparent, translucent
  • H05K9/0096—Shielding materials being light-transmitting, e.g. transparent, translucent for television displays, e.g. plasma display panel

Definitions

• the present invention relates to a method for preparing a black surface-treated copper foil for electromagnetic radiation shielding and a copper foil produced by the method, which has low light reflectance and no stain, and hardly has residues, thereby having a uniform and consistent appearance.
• Background Art [2] Plasma display panel shows strong electromagnetic radiation which may be un ⁇ desirable to the health of human, from the display screen, therefore it is required to prevent such electromagnetic radiation by forming an electromagnetic radiation shield.
• a conventional electromagnetic radiation shield a composite material, which is produced by laminating a copper circuit to an insulating transparent base layer such as PET and the like has been used, wherein the composite material has advantages of an excellent electromagnetic shielding effect and light transmission.
• the composite material is produced by laminating a copper foil having a certain surface roughness onto the transparent base layer, and removing unnecessary parts of the copper foil by etching so as to form a copper circuit with a desired pattern.
• Appropriate circuit line width and pattern of the copper circuit are selected based on the required level of electromagnetic shielding capability and light transmission.
• the object of the present invention is to provide a surface-blackened copper foil for electromagnetic radiation shielding, which has low reflectance owing to its black- colored surface.
• another object of the present invention is to provide a surface-blackened copper foil which has a uniform appearance hardly having stains or residues, even though the copper foil has a black-colored surface, and exhibits excellent etching property and chemical resistance, and further a method for manufacturing the same.
• a method for producing a surface-blackened copper foil for electromagnetic radiation shielding specifically a method for producing a surface-treated copper foil for electromagnetic radiation shielding which comprises placing a copper foil as a cathode in an elec ⁇ troplating bath and forming a black plated layer on the surface of the copper foil, which is characterized by using an electroplating bath, which comprises Co, Ni, an ammonium compound and a chelating agent to form a black plated layer comprising Co and Ni on the surface of said copper foil.
• the electroplating bath may further additionally comprise any one or more of Fe, Cu, Zn, Cr, Mo, W, V, Mn, Ti and Sn, thereby preferably forming a black plated layer which comprises essentially Co and Ni, and optionally any one or more of Fe, Cu, Zn, Cr, Mo, W, V, Mn, Ti and Sn.
• the ammonium compound may include ammonium salts and ammonium complex.
• the chelating agent may be at least one selected from glycine, citrates and py ⁇ rophosphates.
• the method according to the present invention further comprises a step of forming a deposited layer of fine copper particles on the surface of the copper foil, before forming said black plated layer comprising Co and Ni.
• the method according to the present invention comprises an additional step of forming a layer of electrolytic chromate on said black plated layer comprising Co and Ni.
• the method according to the present invention comprises an additional step of forming a plated layer comprised of Zn or Zn-alloy on the other side of the surface of the copper foil where said plated layer is formed.
• a plated layer comprised of Zn or Zn-alloy on the other side of the surface of the copper foil where said plated layer is formed.
• the copper foil for electromagnetic radiation shielding is an electrolytic copper foil which may be available for the production with wide width, wherein the thickness of said copper foil is 1-35D, and preferably 6-18D, and the surface roughness (Rz: DIN) of said copper foil is 0.1-2.0 D, and preferably 0.5-1.5 D.
• the surface treatment of the copper foil for blackening is carried out by placing a copper foil as a cathode in an electroplating bath, which contains metal that develops black color, and depositing the metal layer onto the surface of said copper foil cathode.
• the black color-developing metals Cu, Cr, Co, Ni and the like are known in this field of art.
• Cu may develop complete black color, it causes a problem of damaging a copper foil circuit pattern by permeating into the copper foil circuit during the formation of the circuit pattern, and Cr adversely affects to the etching performance in the formation of a copper foil circuit, thus theses are not suitably applicable to the present invention.
• Co and Ni are the most suitably applicable metal in the present invention.
• the present invention provides a black-surface treated copper foil comprising a black plated layer having uniform and consistent appearance, by forming a black plated layer on a copper foil through a method so-called a complex-ion plating process, which comprises adding an ammonium compound to a Co- and Ni-containing elec ⁇ troplating bath, and forming a complex compound by chemically binding ammonium, as a ligand, to the central metal ions, Co and Ni.
• a complex-ion plating process which comprises adding an ammonium compound to a Co- and Ni-containing elec ⁇ troplating bath, and forming a complex compound by chemically binding ammonium, as a ligand, to the central metal ions, Co and Ni.
• the plating of Co and Ni to the copper foil through the complex-ion plating process makes the plating process comprising Co and Ni totally different from the conventional plating process where ammonium compounds are not introduced, and thus non-uniform plating as occurred in conventional methods can be successfully prevented.
• the black plated layer comprising Co and Ni formed by said process has advantages of excellent etching property and chemical resistance in later etching process for the formation of copper circuit patterns.
• the plating process may be carried out by using an Ir electrode as an anode and a copper foil as a cathode.
• each concentration of Co and Ni in the electroplating bath is less than 1 g/1, the plated layer does not develop complete black color, on the other hand, when it is more than 20 g/1, residues may be generated disadvantageously by being smeared. Therefore, each concentration of Co and Ni contained in the electroplating bath is preferably in the range of 1-20 g/1, respectively.
• those additional components should be contained in the plating bath at least 1 g/1 or more. However, when the additional components are excessively introduced to the plating bath, the plated layer may not develop complete black color, therefore the upper limit of the additional components is preferably 1-10 g/1.
• the ammonium compound being used as a ligand ammonium salts such as ammonium sulfate, ammonium chloride, ammonium acetate and the like may be used, and ammonium compounds in the form of ammonium complex compound may also be used. When the concentration of the ammonium compounds in the plating bath is more than 50 g/1, the plated layer may not have complete black color, therefore it is preferably 50 g/1 or less.
• the concentration of the ammonium compounds is more preferably 1-50 g/1.
• the chelating agent for binding ammonium with central metal ions glycine, citrates, pyrophosphates and the like may be suitably used.
• the concentration of the chelating agent is more than 100 g/1, complete black color may not be developed and stains may be occurred on the surface of the copper foil, therefore it is preferably 100 g/1 or less.
• the concentration of the chelating agent is desirably 5 g/1 or more. Therefore, the concentration of the chelating agent is more preferably 5-100 g/1.
• current density is in the range of 0.1-60 A/ dm , and preferably in the range of 5-45 A/dm . When the current density is less than 0.1 A/dm , the desired black plated layer cannot be obtained and when the current density is not less than 60 A/dm , plating is achieved so excessively that residues tends to come off easily and stained.
• the pH value of a plating bath is preferably in the range of 2.5-6.0, and more preferably 4.0-5.8.
• the plating time may be in the range of 1-40 seconds, but the plating time out of said range is also possible, depending on the current density, the concentration of electrolytic liquid and the like.
• a layer of fine copper particles may be deposited onto the surface of the copper foil before carrying out plating for blackening.
• the deposited copper particles are served as an anchor so that the adhesiveness may become improved by increased peel strength in layering the copper foil onto the transparent substrate, and reduce the reflectance by diffused reflection of external light.
• the fine copper particles may be formed by a treatment for roughing, which is applied to a copper foil for a printed circuit board(PCB). Such treatment for roughing is typically carried out in a plating bath of copper sulfate, and the amount of copper particles attached during the roughing process is preferably in the range of 0.1-10 g/D, and more preferably in the range of 0.5-8 g/D.
• the surface roughness should be maintained in the range of 0.1 -2.0D in Rz (DIN standard) as described above.
• Rz DIN standard
• an anticorrosive treatment may be made to the copper foil according to the present invention, for example electrolytic chromate treatment and the like. Ad ⁇ ditionally, when plating Zn or Zn-alloy on the surface of the copper foil where the black plated layer is not formed, it is possible to prevent discoloration during a heating process in manufacturing an electromagnetic radiation shield.
• a surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an anticorrosive treatment by using Cr.
• Example 2 [45] A layer of fine copper particles was formed with an amount of copper attached thereto of 1.5 g/m 2 , and then a plating process for blackening and anticorrosive treatment were carried out under the same conditions as in Example 1.
• Example 3 [47] The surface of a copper foil was pretreated under the same conditions as in Example 1, and then the surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an an- ticorrosive treatment by using Cr.
• Example 4 The surface of a copper foil was pretreated under the same conditions as in Example 1, and then the surface conventionally called as a matte side of the copper foil was subjected to a plating process for blackening under the conditions as in Example 3. After the plating process for blackening, the blackened surface was subjected to an an- ticorrosive treatment by using Cr. [55] Example 5 [56] An electrolytic copper foil having a surface roughness(Rz) of 2D or less and a thickness of 18D was immersed into 100 g/1 of sulfuric acid for 5 seconds, and washed with acid and then with pure water.
• a surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an anticorrosive treatment by using Cr.
• Example 6 An electrolytic copper foil having a surface roughness(Rz) of 2D or less and a thickness of 18D was immersed into 100 g/1 of sulfuric acid for 5 seconds, and washed with acid and then with pure water. Then, a surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an anticorrosive treatment by using Cr.
• Example 7 The surface of a copper foil was pretreated under the same conditions as in Example 1, and then the surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an an- ticorrosive treatment by using Cr.
• Example 8 An electrolytic copper foil having a surface roughness(Rz) of 2D or less and a thickness of 18D was immersed into 100 g/1 of sulfuric acid for 5 seconds, and washed with acid and then with pure water. Then, a surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an anticorrosive treatment by using Cr.
• Example 8 An electrolytic copper foil having a surface roughness(Rz) of 2D or less and a thickness of 18D was immersed into 100 g/1 of sulfuric acid for 5 seconds, and washed with acid and then with pure water. Then, a surface conventionally called as a shiny side of the copper foil was subjected to a plating process for blackening under the conditions given below. After the plating process for blackening, the blackened surface was subjected to an anticorrosive treatment by using Cr.
• Comparative example 1 Electroplating was carried out under the same conditions as in Example 1, except that ammonium sulfate was not used.
• Comparative example 2 Electroplating was carried out under the same conditions as in Example 1, except that the concentration of (NH ) SO was 60 g/1.
• Comparative example 3 Electroplating was carried out under the same conditions as in Example 1, except that sodium citrate was not used.
• Comparative example 4 Electroplating was carried out under the same conditions as in Example 1, except that the concentration of sodium citrate was 120 g/1.
• Etching property was determined by the presence of etching residues after a step comprised of laminating the blackened surface of the copper foil to FR-4 resin and immersing the laminated resin into a ferric chloride etching solution at 50°C for 15 minutes.
• Chemical resistance was determined by a method comprised of laminating the blackened surface of the copper foil to FR-4 resin, forming a circuit having the width of 400D on the blackened surface with ink, etching the resulted circuit under the same conditions as in the estimation of etching property, removing ink with IN NaOH at 50°C, and determining the degree of permeation of the etching solution to the comer of the circuit pattern remained after the above etching step by using a polarized microscope. [104] Table 1
• Example 7 where Fe was additionally used, showed significantly rapid reaction rate in the etching step as compared to other examples 1-6 and no generation of etching residues, and Example 8 which Zn was additionally used, showed excellent peel strength. Further, Example 2 where fine copper particles were plated before elec ⁇ troplating for blackening, and Example 4 where electroplating was carried out on the matte side showed high peel strength.
• the surface-treated copper foil produced by the method of the present invention has black-colored appearance which has low reflectance, therefore providing an advantage that it does not degrade the brightness of the PDP screen.
• the surface-treated copper foil produced by the present invention has a uniform appearance without stains or residues even though it has black-colored appearance, and excellent etching property and chemical resistance, a composite material for an electromagnetic radiation shield using the same may be produced with a significantly lowered defective rate, and the screen of a PDP manufactured by using said composite material will have excellent appearance.

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• 2004
  • 2004-06-02 KR KR1020040039902A patent/KR100633790B1/ko active IP Right Grant
  • 2004-07-12 JP JP2004204150A patent/JP4309817B2/ja active Active
• 2005
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