Printed circuit board and method and apparatus for making same
AssigneeHitachi, Ltd.
InventorsKiyonori Kogawa, Nobuaki Ooki, Masami Kawaguchi, Motoyo Wajima, Haruo Akahoshi, Akira Nagai
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Abstract
The present invention provides a printed circuit board which is high in acid resistance, mechanical strength at high temperature and bond strength, a method for making the printed circuit board and an apparatus used for making the printed circuit board. The technique of the present invention is characterized in that a metallic film having metal particles discretely distributed therein is provided on a roughened surface of copper circuit pattern on an insulating substrate which has been oxidized to form copper oxide and thereafter reduced.
Claims14
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.
A method for making a primed 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;
- a step of forming dark brown/black copper oxide on the roughened surface of copper circuit pattern on the insulating substrate using an oxidizing agent;
- a step of reducing said copper oxide;
- and
- a plating step of forming a metallic film having nickel or cobalt metal particles discretely distributed therein on the surface of said reduced copper oxide in a plating solution containing a nickel salt or a cobalt salt and a boron compound free from palladium:
- wherein no treatment with water is carried out between the step of reducing and the plating step.
Dependencies are inferred from the claim text.