Electromigration Characteristics and Morphological Evolution of Cu Interconnects on CVD Co and Ru Liners for 10-nm Class VLSI Technology

• Published in: IEEE electron device letters 2018-07, Vol.39 (7), p.1050-1053
• Main Authors: Jang, Kyung-Tae, Lee, So-Yeon, Na, Se-Kwon, Lee, Sol-Kyu, Baek, Jong-Min, You, Woo-Kyung, Park, Ok-Hee, Kim, Rak-Hwan, Oh, Hyeok-Sang, Joo, Young-Chang
• Format: Article
• Language: English
• Subjects: Acceleration; Annealing; Barriers; Chemical vapor deposition; cobalt; Copper; CVD liner; Electromigration; electromigration (EM); Evolution; Integrated circuit interconnections; Integrated circuits; Interconnections; interconnects; Linings; Organic chemistry; Physical vapor deposition; Reliability; Resistance; Ruthenium; Tantalum; Very large scale integration
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2018.2840507

Ruthenium (Ru) and cobalt (Co) are new candidates for the replacement of physical vapor deposition tantalum (Ta) in liner materials because Ru and Co have excellent Cu-filling properties when deposited using chemical vapor deposition (CVD). Under accelerated current stressing conditions, Cu interconnects on a TaN/Co barrier showed an abrupt increase in resistance. The Cu resistance on a TaN/Ru barrier increased gradually and saturated with low deviation because voids generated randomly, and the Cu that remained on the Ru in the voids acted as shunt layers, preventing a sudden increase in resistance. Cu evolution tests on a Ru liner indicated that Cu had a strong bond with CVD Ru liner, even at high temperatures. These results suggest that Cu deposited on a TaN/Ru barrier can endure electromigration failure.