Impact of low-k dielectrics and barrier metals on TDDB lifetime of Cu interconnects

• DOI: 10.1109/relphy.2001.922927
• Publication Date: 2002-11-13T15:01:54Z
• Authors: J. Noguchi; T. Saito; N. Ohashi; H. Ashihara; H. Maruyama; M. Kubo; H. Yamaguchi; D. Ryuzaki; K.-I. Takeda; K. Hinode
• Keywords: Dielectric strength; Diffusion barrier; Low-k dielectric

Time-dependent dielectric breakdown (TDDB) in Cu metallization and the dependence on presence of barrier metal, metal thickness, kind metals low-k dielectrics, is investigated. There a distinct difference TDDB degradation mechanism with without metals. interconnects caused by bulk mode CMP-surface mode, respectively. The characteristics are almost same for different thicknesses depends much more strongly electric field strength than MIS structure. Additionally, both degradations, related to Cu-ion diffusion, mainly not thermal stress but electrical stress. properties Ta TaN better those TiN against diffusion into TDDB. In case structure, also depend CMP-surface. With concentrated near CMP surface lifetime reduces as k-value decreases. However, all structures this study able satisfy 10-year reliability specifications capacitor.