The Nucleation and Growth of Electroless Metal Deposited onto Plastic Substrates

Summary

A technique is described for obtaining electron micrographs of very thin electroless metal films deposited on plastic substrates. During the early stages of growth, electroless metals are deposited as island structures, growth beginning at active sites created by the stannous chloride/palladium chloride treatment. These active palladium sites are less numerous on surfaces where the depositing metal is “chemically bonded” to the plastic than on those where it is not. The growth and structure of electroless copper and nickel are compared. Copper is deposited as a crystalline solid, whereas nickel appears to behave as a quasi-liquid. The chemistry of the surface of the plastic is found to influence the nucleation and subsequent growth of the electroless deposit. A theory is presented which explains the variation of he island density of electroless nickel with deposition temperature.