Grain structure and crystallographic orientation of Cu damascene architecture lines with widths ranging from 0.5 to 4 μm depending on linewidth and anneal conditions affected the electromigration (EM) performance. The grain size of Cu lines was affected by the constraints of the trench sidewall and then decreased as the linewidth was reduced. A small grain and a weaker (1 1 1) texture in the Cu line were formed compared with that in the blanket Cu film form due to the trench sidewalls serving as grain nucleating and growing sites. The mean time to EM failures of the Cu metallization was improved via the grain growth and (1 1 1) texture evolution during anneal at 300 °C for 30 min. The results included that the Cu diffusion involves interface diffusion and boundary transport, while dominant diffusion pathways are the sidewall interface diffusion for narrow lines. © 2003 Elsevier B.V. All rights reserved.
Ji, Y., Zhong, T., Li, Z., Wang, X., Luo, D., Xia, Y., & Liu, Z. (2004). Grain structure and crystallographic orientation in Cu damascene lines. Microelectronic Engineering, 71(2), 182–189. https://doi.org/10.1016/j.mee.2003.11.002