Integration Aspects of CoWP Capping Layers for Electromigration Enhancement

CoWP metal caps have been integrated into 65nm- and 45nm-node copper interconnects. A number of CoWP specific integration aspects have been investigated. Electrical performance, reliability and yield potential were characterized on a statistical base. Substantial progress has been made to suppress the CoWP related time-depended dielectric breakdown (TDDB) degradation making CoWP the option to solve the electromigration (EM) challenge for 32nm and beyond.