Copper alloy foil

Abstract

For a three-layer flexible board, there is provided a copper alloy foil that requires no roughening processing, that has good adhesion with an adhesive containing an epoxy resin, that can be laminated to form a copper-clad laminate, that has a low surface roughness, and that has high conductivity and strength. The copper alloy of the foil contains at least one of 0.01-2.0 weight percent Cr and 0.01-1.0 weight percent Zr or contains 1.0-4-8 weight percent Ni and 0.2-1.4 weight percent Si. Good adhesion of the copper alloy foil to a resin substrate with an adhesive containing an epoxy resin is obtained by setting the thickness of the anticorrosive coating to less than 3 nm; the surface roughness of the copper alloy foil is below 2 μm expressed as ten-point average surface roughness (Rz); and, without roughening processing, the 180° C. peel strength, after adhesion of the copper alloy foil to the board film by means of an adhesive containing an epoxy resin, is greater than 8.0 N/cm.

1 . Copper alloy foil for lamination with a resin substrate, the copper alloy foil consisting essentially of at least one of 0.01-2.0 weight percent Cr and 0.01-1.0 weight percent Zr, the balance copper and unavoidable impurities, the copper alloy foil having an anticorrosive coating of thickness less than 3 nm, the copper alloy foil having a surface exhibiting no artificial roughening and having a surface roughness less than 2 μm expressed as ten-point average surface roughness, tensile strength greater than 600 N/mm 2  and conductivity greater than 60% IACS, and 180° peel strength between the copper alloy foil and an adhesive containing an epoxy resin bonding the copper alloy foil to a resin substrate is greater than 8.0 N/cm.  
     
     
         2 . Copper alloy foil for lamination with a resin substrate, the copper alloy foil consisting essentially of 1.0-4.8 weight percent Ni, 0.1-1.4 weight percent Si, the balance copper and unavoidable impurities, the copper alloy foil having an anticorrosive coating of thickness less than 3 nm, the copper alloy foil having a surface exhibiting no artificial roughening and having a surface roughness less than 2 μm expressed as ten-point average surface roughness, tensile strength greater than 650 N/mm 2  and conductivity greater than 40% IACS, and 180° peel strength between the copper alloy foil and an adhesive containing an epoxy resin bonding the copper alloy foil to a resin substrate is greater than 8.0 N/cm.  
     
     
         3 . Copper alloy foil according to  claim 1  or  2 , wherein the anticorrosive coating comprises at least one nitrogen-containing organic compound which forms a chelate with the copper.  
     
     
         4 . Copper alloy foil according to  claim 1  or  2 , wherein the organic compound is selected from the group consisting of benzotriazole and imidazole.  
     
     
         5 . Copper alloy foil according to  claim 1  or  2 , wherein the resin of the resin foil is a polyimide.  
     
     
         6 . A laminate comprising a copper alloy foil according to  claim 1  or  2  laminated with a resin substrate.  
     
     
         7 . The laminate of  claim 6 , further comprising a resin-containing adhesive bonding the copper alloy foil to the resin substrate.  
     
     
         8 . The laminate of  claim 7 , wherein the resin of the resin-containing adhesive comprises an epoxy.