The improvement of copper interconnect electromigration resistance by cap/dielectric interface treatment and geometrical design

A significant improvement of electromigration (EM) lifetime is achieved by modification of pre-clean before cap-layer deposition and Cu cap/dielectric materials. A possible mechanism for EM lifetime enhancement was proposed. Cu-silicide formation before cap-layer deposition and adhesion of Cu/cap interface were found to be critical factors in controlling Cu electromigration reliability. Effects of geometrical layout variation and stress current direction were also investigated.