Main Articel: [[Electroless Plating| Electroless Plating]]
====7.1.2.3 Electroless Processes====
The electroless metal plating with adding reduction agents to the electrolyte is
based on the oxidation of the reducing agent with release of electrons which
then in turn reduce the metal ions. To achieve a controlled deposition from such
solutions the metal deposition has to happen through the catalytic influence of
the substrate surface.
Otherwise a “wild” uncontrollable deposition would occur. In most cases
palladium containing solutions are used for the activation which seed the
surfaces with palladium and act as catalysts in the copper and nickel
electrolytes.
The electrolytes contain besides the complex ion compounds of the metals to
be deposited also stabilizers, buffer and accelerator chemicals, and a suitable
reduction agent.
These electrolytes are usually operating at elevated temperatures (50° – 90°C).
The deposits contain besides the metals also process related foreign inclusions
such as for example decomposition products of the reduction agents.
The electroless processes are used mainly for copper, nickel, and gold
deposits.
====7.1.2.4 Electroless Deposition of Nickel/Gold====