Abstract:
Disclosed is a method of plating a substrate with a metal using an autocatalytic electroless plating bath wherein the bath is operated above its cloud point temperature such that at least two phases are present in the bath. An autocatalytic electroless plating bath for coating silver metal is also described. A method for autocatalytic plating of silver metal directly onto a silicon surface without the need for an intervening layer of metal is also disclosed. The deposits of silver obtained are uniform, non-porous and have electrical properties . The technique can be applied for different processes and bath formulations i.e. different metals, complexing agents and reducing agents .
Abstract:
The present invention provides a method for plating an object with a metal coating, allowing uniform coatings to be applied, even inside cavities in the object. The method comprises the steps of: bringing the object into contact with a solution comprising metal ions; bringing a counter electrode into contact with said solution comprising metal ions; connecting an electrical circuit between the object and the counter electrode; applying a constant DC current I1 to the electrical circuit for a time period t-, so as to provide a current density A-i on the surface of the object so that the object becomes plated with a metal coating; applying a second constant DC current I2 in the opposite direction as I1 to the electrical circuit for a time period t2 so as to provide a current density A2 on the surface of the object; applying a third constant DC current I3 in the same direction as Ii to the electrical circuit for a time period t3 so as to provide a current density A3 on the surface of the object. The plating steps may be repeated until the object is plated with the required profile of the metal. The invention further relates to an object plated according to the described method, and to an apparatus for carrying out the method. The invention also relates to the pulse sequence of the described method, and a set of instructions for carrying out the pulse sequence of the described method.