Abstract: A gas phase plasma cleaning method and apparatus is shown for removing contaminants from the surface of exposed metallic parts on integrated circuits (IC's). A two step method is shown using a defined gas mixture of argon and oxygen, and ammonia and hydrogen. The gases are separately introduced into a plasma chamber. The argon oxygen mixture is used to remove carbonatious material by chemical reaction and by milling. The ammonia hydrogen mixture is introduced to chemically remove and reduce oxides and phosphates. Surface energies are increased to permit improved adhesion of inks. Additionally, intermediate oxides formed after the plasma exposure prevent complete regrowth of the normally passivating oxide layer.

Abstract: A process for removing unwanted contaminant metallic oxide from the surface of a nickel branding layer of an electronic circuit package, in order to enhance the affinity of a layer of phenolic branding ink to the surface of the metallic branding layer involves treating the surface of the metallic branding layer with a hydrogen-containing, chemical reducing gas phase ambient, so that oxygen within the surface oxide chemically combines with the hydrogen component within the ambient, so as to form readily removable water. The surface of the metallic branding layer is thereby substantially free of surface oxide, providing a greater surface area of metallic-ink bonding sites. As a consequently, a subsequently deposited layer of branding ink strongly adheres to the surface of the nickel and is not readily removed during further cleaning of the circuit package.