Thermally stable dual metal coated laminate products made from polyimide film

摘要

Bath surfaces of a polyimide sheet are coated with a layer of electroless nickel or cobalt which can also include a thin electroless copper layer on the Ni. or Co. This tenaciously bonded coating is subsequently treated in such a way so as to increase its permeability or porosity without substantially altering its resistive properties. The induced porosity allows water and other volatiles trapped in the dielectric polyimide sheet to be removed while the preserved electrical continuity of the metal layer is sufficient to support electrolytic copper plating which services the dual purpose of providing a copper thickness useful for the subsequent production of electronic circuitry and preventing the readsorption of water into the dielectric core by permanently sealing or coating said porous metal layer.