Method of treating the surface of the copper foil used in printed wire boards

摘要

The present invention relates to a method of treating the surface of the copper foil used in printed wire boards, in which the copper foil, of which the surface thereof was preliminarily roughened, is electrolytically treated in an aqueous solution of zinc chromate containing zinc ions and chromium (VI) ions at a definite range of ratio; the thus-treated copper foil is then preferably immersed in an aqueous solution containing amino silane, sodium silicate and/or potassium silicate at a definite ratio. The use of the so-treated copper foil in multi-layer glass/epoxy printed wire boards (NEMA grade, FR4, FR5) serves to prevent the generation of brown spottings and the elimination of the delamination of the copper conductors. In addition, the use of the so treated copper foil in flame resistant paper/phenol printed wiring boards (NEMA grade FR2) leads to the elimination of the poor adhesive properties and delamination of copper conductors.