Suppression of electromigration early failure of Cu/Porous low-k interconnects using dummy metal

Yumi Kakuhara, Shinji Yokogawa, Masayuki Hiroi, Toshiyuki Takewaki, Kazuyoshi Ueno

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Abstract

The electromigration (EM) lifetime of Cu/porous low-k interconnects was evaluated by EM experiments in which the effect of back-flow stress was negligible. The EM lifetime of the downstream mode was reduced using a porous low-k film (SiOCH) as an intermetal dielectric (IMD) in comparison with using a SiO2 dielectric. The reduction in EM lifetime was observed only at low cumulative failure probability, considered as ''early failure''. The early failure was caused by the formation of a slit void under a via. It was found that the early failure was suppressed by placing a dummy metal near the metal/via contact that inhibited the formation of a slit void. The EM degradation of Cu/ porous low-k interconnects is likely to be caused by the mechanical properties of porous low-k film. The dummy metal supports the porous low-k film near the metal/via contact, which leads to improved EM.

Original languageEnglish
Pages (from-to)965041-965045
Number of pages5
JournalJapanese Journal of Applied Physics
Volume48
Issue number9 Part 1
DOIs
Publication statusPublished - 2009 Dec 1

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ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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