The application of ALD WN/sub x/C/sub y/ as a copper diffusion barrier

A 2.7 nm ALD WN/sub x/C/sub y/ copper barrier was integrated into fully functional backend dual-damascene devices built in SiO/sub 2/ on 200-mm wafers at International Sematech. Electromigration results were extraordinary, with average time to failure more than 10 times longer than standard PVD Ta. Electrical and physical results suggest that ultrathin WN/sub x/C/sub Y/ is an excellent copper barrier and meets the requirements for integration, including: Via resistance, electromigration, barrier integrity, film continuity, etc.