Improved Cleaning Method to Remove Sputter Byproducts
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-29
Prior to the deposition of terminal metallurgy, an energetic pre-clean is needed to remove metal oxides and residual organics from the underlying aluminum device interconnection metallurgy. This insures low contact resistance between the terminal metallurgy and the aluminum. The pre-clean process is an argon sputter clean under an RF power supply. As this sputter process is indiscriminate as to the atoms removed, the sputter tool gradually accumulates complex byproducts in its chamber. In particular, metal residues from the terminal metallurgy tooling fixtures and carbon residues from the organic passivation on the wafer. Once the accumulated byproducts reach a certain level, the pre-clean process conditions are altered and the required contact resistance cannot be maintained. At this point, the tool must be cleaned.