Plasma cleaning method for improved ink brand permanency on IC packages with metallic parts

摘要

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.