Method for electroless nickel deposition onto copper without activation with palladium

Abstract

The invention relates to selective deposition of a nickel layer on a copper surface. The invention may be used in the production of electrically conductive areas for electronic circuits. Method for nickel deposition on the surface of copper comprises immersing an item, which surface is to be deposited with the nickel layer, into one or more baths, of which at least one contains a reducing agent and of which at least one is adapted for (electroless) plating of nickel. In order to extend the field of application and to obtain practically pure nickel coatings, said reducing agent comprises boronic or phosphoric compounds, comprising morpholine borane (C4H9BNO), or dimethylamine borane (C2H7BN), or sodium tetrahydroborate (NaBH4), or sodium hypophosphite (NaH2PO2) and said reducing agent directly or indirectly reduces insoluble copper (I) or copper (II) compounds on the copper surface. At least one of the mention baths comprises a ligand or mixture thereof.

Dependencies are inferred from the claim text.