Grain structure analysis and effect on electromigration reliability in nanoscale Cu interconnects

Appl. Phys. Lett. 102, 131907 (2013)

Linjun Cao, K. J. Ganesh, Lijuan Zhang, Oliver Aubel, Christian Hennesthal, Meike Hauschildt, Paulo J. Ferreira, Paul S. Ho.

 

Laboratory for Interconnect and Packaging, Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78712, USA and

Materials Science and Engineering Program, The University of Texas at Austin, Austin, Texas 78712, USA and

GLOBALFOUNDRIES Dresden Module One LLC & Co. KG, 01109 Dresden, Germany.

 

Abstract

 

The grain structure in Cu interconnects of the 45 nm node was analyzed to yield grain orientation and boundary characteristics using a high-resolution electron diffraction technique. A dominant sidewall growth of {111} grains was observed, reflecting the importance of interfacial energy in controlling grain growth below 70 nm linewidth. The grain structure was used to identify flux divergent sites for void formation under electromigration (EM) and to analyzethe effect on EM statistics for Cu lines with CoWP capping using a microstructure-based model. This analysis established a correlation between the microstructure of Cu nanolines, voidformation kinetics, and EM statistics.

© 2013 American Institute of Physics

 

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Cu interconnects

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