Self-Aligned Barrier Improves Interconnect Reliability

A new PECVD self-aligned barrier using a germanium dopant offers a simple, cost-effective means of improving electromigration resistance of copper interconnects. Germanium has long been recognized as one of the chemicals of choice for these applications. Recently, a novel technique for Ge-PSAB was developed. Process integration testing of the Ge-PSAB process using 65 nm node features and a dual damascene scheme with Coral bulk low-k dielectric. Two metal layer damascene structures were used for reliability investigation. Comb capacitor line-to-line dielectric breakdown data collected from test structures with 80 nm spaces showed that Ge-PSAB and the control processes provide a statistically equivalent breakdown performance.