Analytical modeling of reservoir effect on electromigration in Cu interconnects

• Main Authors: Zaporozhets, T., Tu, K. N., Gusak, A. M., Shao, W., Gan, Zhenghao, Chen, Zhong, Mhaisalkar, Subodh Gautam
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Materials
• Online Access: https://hdl.handle.net/10356/94251; http://hdl.handle.net/10220/7709
• Institution: Nanyang Technological University

Electromigration (EM) in Cu dual-damascene interconnects with extensions (also described as overhangs or reservoirs) ranging from 0 to 120 nm in the upper metal (M2) was investigated by an analytical model considering the work of electron wind and surface/interface energy. It was found that there exists a critical extension length beyond which increasing extension lengths ceases to prolong electromigration lifetimes. The critical extension length is a function of void size and electrical field gradient. The analytical model agrees very well with existing experimental results. Some design guidelines for electromigration-resistant circuits could be generated by the model.