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Printed circuit board and method and apparatus for making same

  • US 5,472,563 A
  • Filed: 06/24/1994
  • Issued: 12/05/1995
  • Est. Priority Date: 09/22/1989
  • Status: Expired due to Fees
First Claim
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1. A method for making a multi-layer printed circuit board having a higher mechanical strength at an increased temperature, the method comprising:

  • a step of etching a copper surface of copper circuit pattern on an insulating substrate to roughen the copper surface;

    an oxidizing step of forming a dark brown/black copper oxide layer on the roughened surface of copper circuit pattern on both sides of the insulating substrate using an oxidizing agent;

    a reducing step of forming a reduced copper layer by reducing the copper oxide layer;

    a plating step of forming a metallic film having nickel or cobalt metal particles discretely distributed thereon on the surface of the reduced copper oxide layer in a plating solution containing a nickel salt or a cobalt salt and a boron compound free from palladium to form a layered body; and

    a step of water washing and drying the layered body and then laminating a plurality of the layered bodies, each separated by an insulating resin layer, followed by bonding the insulating resin layers under pressure;

    wherein no treatment with water is carried out between the reducing step and the plating step.

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