GB1126327A - Electroless copper plating - Google Patents

Abstract

1,126,327. Electroless copper deposition. PHOTOCIRCUITS CORP. April 26, 1966 [April 27, 1965], No.18155/66. Heading C7F. In a process for the electroless deposition of Cu on metallic or non-metallic substrates an aqueous solution of a Cu salt contains a complexing agent, a reducing agent, a pH adjuster and at least 0À1 microgram atoms per litre of a compound containing an element selected from the group consisting of Mo, Nb, W, Re, V, As, Sb, Bi, Ac, La, the rare earths or mixtures of these. Examples of the stabilizing compounds added are MoO 3 , ammonium molybdate, oxides of W, V, Re and As, the tungstates, vanadates, arsenates and rhenates of Groups 1A and 11A and ammonium, the oxides, sulphates, nitrates, halides and acetates of Sb, Bi, La, Ac and the rare earths and the preferred concentration is 0À1-1,000 microgram atoms per litre. The pH of the solution is maintained at 10-14 by the addition of alkali metal hydroxide and the reducing agent is formaldehyde. Less than 5gms/litre of surfactants such as organic phosphate esters and oxyethylated salts may be added. Non-metallic substrates which are to be coated are first sensitized with an acid solution of SnCl 2 and PdCl 2 .