Improving the barrier ability of Ti in Cu through-silicon vias through vacuum annealing

Murugesan Mariappan, Jichoru Be, Takafumi Fukushima, Eiji Ikenaga, Hiroshi Nohira, Mitsumasa Koyanagi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Suppressing leak current and blocking Cu diffusion into active Si from Cu through-silicon vias (TSVs) are important requirements for enhancing three-dimensional (3D) LSI performance and reliability. We have proposed and confirmed a cost effective means of enhancing the barrier property of sputtered Ti in high-aspect-ratio Cu-TSVs by simple vacuum annealing at 400 °C for 20 min. The self-formed amorphous TiSi2 at the interface between dielectric SiO2 (along the TSV side-wall) and barrier Ti layer is found to play a positive role in improving the leak current characteristics. As-formed TiSix was partially converted into TiO2 and SiO2 during the vacuum annealing above 200 °C, and nearly vanished after annealing at 400 °C. The immense importance of 400 °C vacuum-annealing is not only in terms of the improvement in the barrier characteristics of the Ti layer, but also it is being a prerequisite for preventing Cu popup in 3D-LSI. Both the X-ray photoelectron spectroscopy (XPS) and current-voltage (I-V) data clearly reveal that this simple vacuum annealing of Cu-TSVs at 400 °C has tremendous potential for implementation in cost-effective via-last 3D integration.

Original languageEnglish
Article number04CC08
JournalJapanese journal of applied physics
Volume56
Issue number4
DOIs
Publication statusPublished - 2017 Apr 1

ASJC Scopus subject areas

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

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