SURFACE TREATING METHOD OF COPPER AND COPPER ALLOY

PURPOSE:To continuously and uniformly execute surface treatment when copper- base metal is etched in an aq. soln. containing ferric chloride by feeding the aq. soln. in accordance with the measured value of the oxidation-reduction potential of the etching solution. CONSTITUTION:When the surface of copper or copper alloy is cleaned, roughened and activated by treating in the etching solution consisting of an aq. soln. containing ferric chloride, the oxidation-reduction potential of the etching solution is measured. Then, copper-base metal is etched while the composition of the etching solution is always kept constant by feeding the new liquid of the aq. soln. containing ferric chloride so as to maintain the oxidation- reduction potential near to a set value. Because a surfactant can be added to the etching solution, defatting can be executed simultaneously with etching, and the simplified equipment and the high productivity can be attained. Furthermor, an antioxidant can be added to the etching solution.