Electroless Copper Initiation "Take" Improvement by the Addition of Trace Metal Ions
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
To initiate electroless copper plating a catalyst is needed. Palladium (Pd) is the most commonly used metal for initiation and is deposited in a two-step operation: Sn2+ is adsorbed onto the non-conductive substrate from a SnCl2 solution, followed by the reduction of Pd2+ . Sn2+ is oxidized to Sn4+ in the reaction. The addition of other ions to the Pd Cl2 activation solution can affect the reducing agents' catalytic activity. The addition of parts per million (ppm) amounts of Ag+ to the Pd C12 solution prior to electroless plating increases the amount of copper deposited in a given time. The Ag+ may be added as Ag NO3 . The addition of Ni+ has also been shown to retard the initiation electroless copper plating.