Method for reducing the optical reflectivity of a copper and copper alloy circuitry and touch screen device

A method for reducing the optical reflectivity of a copper or copper alloy circuitry by depositing thereon a metal layer of palladium or palladium alloy comprising, in this order, the steps of

• (i) providing a dielectric substrate,
• (ii) depositing copper or a copper alloy onto said dielectric substrate with the proviso that said dielectric substrate comprises a plating base when copper or a copper alloy is deposited by electroless (autocatalytic) plating or electroplating, and
• (iii) depositing a palladium or palladium alloy layer onto said copper or copper alloy by immersion-type plating and thereby reducing the optical reflectivity of said copper or copper alloy,
• wherein the palladium or palladium alloy is deposited in step (iii) from an aqueous plating bath comprising a source for palladium ions, an acid and at least one phosphonate compound, and
• wherein by the immersion-type plating the palladium ions are reduced by metallic copper of the deposited copper or copper alloy,
• and wherein the copper or copper alloy deposited in step (ii) is structured to form a circuitry either before step (iii) or after step (iii).