US Patent 7208415 Plasma treatment method for electromigration reduction

A plasma treatment method which is capable of extending the MTF (mean-time-to-failure) of metal interconnects fabricated on a semiconductor wafer substrate, is disclosed. The invention includes providing a trench typically in a dielectric layer on a substrate; depositing a metal in the trench; and exposing the metal to a nitrogen-based plasma. The plasma-treatment step accelerates grain growth and re-orients the grains in the metal to a closely-packed crystal orientation texture which approaches or approximates the <111> crystal orientation texture of copper.