Air gap integration for the 45nm node and beyond

First promising results including reliability and electromigration of an extendable air gap integration approach obtaining mechanically stable air cavities at the inter-metal dielectric (IMD) level are presented. Extraction of the effective dielectric constant (k/sub eff/) is demonstrated to be 1.45 for non-passivated single damascene structures. Using 45 nm node specifications and the proposed integration scheme, two metal levels are simulated showing a k/sub eff/ of less than 2.0 after full integration, fulfilling multiple future interconnect node requirements.