The Potential Benefits of a Chemical “Kick Start” for the Autocatalytic Electroless Copper Plating Process

Electroless copper plating processes have for some time constituted an irreplaceable part of the industrial printed circuit board manufacturing process. Without these processes, it is hard to see how through-hole or multilayer printed circuit boards might be manufactured. One main component of electroless copper plating solutions is the autocatalytic reducing agent which converts the copper from an ionic to a metallic form. Incorporation of such a reducing agent is essential to the working of the process, but brings several drawbacks with it. Many reducing agents have environmentally undesirable aspects and pose health and safety problems. At higher concentrations, they lead to undesirable side-reactions in the bath, apart from which, they can be quite expensive. Some electrolyte additives are discussed which enable copper to be deposited on a palladium-activated substrate, while allowing lower concentrations of a reducing agent in the bath to be used. Use of such an additive can bring advantages in terms of economic, environmental, and health aspects.