| abstract |
A rolled copper or copper alloy foil having a roughened surface comprising fine copper particles, characterized by being obtained by subjecting a rolled copper or copper alloy foil to roughening plating with a plating bath containing copper sulfate (1-50 g/L in terms of Cu amount), 1-150 g/L sulfuric acid, and one or more additives selected among sodium octyl sulfate, sodium decyl sulfate, and sodium dodecyl sulfate under the conditions of a temperature of 20-50 DEG C and a current density of 10-100 A/dm<SP>2</SP>. The rolled copper or copper alloy foil roughened is reduced in craters, which are a conspicuous defect characteristic of rolled copper or copper alloy foils having a roughened surface. Also provided is a rolled copper or copper alloy foil which has a high strength, strength of adhesion to resin layers, acid resistance, and resistance to tin plating solutions. It further has a high peel strength and is satisfactory in suitability for etching and gloss. It is suitable for use in producing a flexible printed wiring board bearing a fine wiring pattern. Furthermore provided is a method of roughening the foil. |