Copper foil for high frequency circuit, method of production and apparatus for production of same, and high frequency circuit using copper foil

Abstract

A copper foil reducing transmission loss at a high frequency and excellent in bond strength with a resin substrate, including at least a granular layer and a columnar layer in its thickness direction, the columnar layer being formed on at least one surface of the granular layer forming the copper foil or the granular layer being formed on at least one surface of the columnar layer forming the copper foil, the relation of the thickness A of the granular layer and the thickness B of the columnar layer in the copper foil being preferably A/(A+B)=40 to 99%, a method of production and apparatus for production for the same, and a high frequency circuit using the same.

1 . A copper foil for a high frequency circuit comprising a columnar layer forming the copper foil and a granular layer formed on at least one surface of the same,
 wherein a relation between a thickness A of the columnar layer forming the copper foil and a thickness B of the granular layer is A/(A+B)=40 to 99%.   
     
     
         2 . A copper foil for a high frequency circuit as set forth in  claim 1 , wherein at least one surface is roughened. 
     
     
         3 . A copper foil for a high frequency circuit as set forth in  claim 1 , wherein at least one surface is subjected to at least one of treating by nickel plating, zinc plating, chrome plating, nickel alloy plating, zinc alloy plating, chrome alloy plating, chromate treatment, organic rust-prevention treatment, and silane coupling agent treatment. 
     
     
         4 . A high frequency circuit fabricated using a copper foil as set forth in  claim 3 . 
     
     
         5 . The copper foil of  claim 1 , wherein an average maximum height of a surface profile of the copper foil is not more than 5.0 μm. 
     
     
         6 . The copper foil of  claim 1 , wherein a roughness average of the copper foil is not more than 0.5 μm.