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Nanotwin formation and its physical properties and effect on reliability of copper interconnects.



Di Xu, Vinay Sriram, Vidvuds Ozolins, Jenn-Ming Yang, K. N. Tu, Gery R. Stafford, Carlos R. Beauchamp, Inka Zienert, Holm Geisler, Petra Hofmann, Ehrenfried Zschech


Ultra-fine grained copper with a large amount of nano-scale twin boundaries has high mechanical strength and maintain normal electrical conductivity. The combination of these properties may lead to promising applications in future Si microelectronic technology, especially as interconnect material for air-gap and free-standing copper technologies. Based on first principles calculations of total energy and in-situ stress measurements, high stress followed by stress relaxation during the Cu film deposition seem to have contributed to nano-twin formation. Nanoindentation studies have shown a larger hardness for copper with a higher nanotwin density. The effect of Cu nanotwin boundaries on grain growth was investigated by Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM). The presence of a high density of nano-twin boundaries may improve the reliability of Cu interconnects.
Microelectronic Engineering


XU, D. , Sriram, V. , Ozolins, V. , Yang, J. , Tu, K. , Stafford, G. , Beauchamp, C. , Zienert, I. , Geisler, H. , Hofmann, P. and Zschech, E. (2008), Nanotwin formation and its physical properties and effect on reliability of copper interconnects., Microelectronic Engineering (Accessed May 20, 2024)


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Created May 2, 2008, Updated October 12, 2021