Reliability of tantalum based diffusion barriers between Cu and Si

T. Laurila*, K. Zeng, A. Seppälä, J. Molarius, I. Suni, J. K. Kivilahti

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

    2 Citations (Scopus)

    Abstract

    The reaction mechanisms in the Si|Ta|Cu and Si|TaC|Cumetallization systems are discussed based on the experimental results and the assessed ternary Si-Ta-Cu, Si-Ta-C and Ta-C-Cu phase diagrams. The ternary Si-Ta-N and Ta-N-Cu phase diagrams were also assessed in order to compare the thermodynamic properties of the TaC diffusion barriers to more widely investigated TaNx diffusion barriers. With the help of the sheet resistance measurements, RBS, XRD, SEM, and TEM the Ta barrier layer was observed to fail above 650 °C due to the formation of TaSi2. This was accompanied by the diffusion of Cu through the silicide layer and the resulting formation of Cu3Si precipitates. The stability of the TaC layers was better and the failure was observed above 750 °C clue to the formation of Cu3Si and TaSi2. However, interdiffusion of Cu and Si was observed already at lower temperatures due to the presence of pinholes in the TaC layer. This emphasises the importance of the fabrication method and the quality of the TaC layers.

    Original languageEnglish
    Title of host publicationMaterials Research Society Symposium - Proceedings
    EditorsG.S. Oehrlein, K. Maex, Y.-C. Joo, S. Ogawa, J.T. Wetzel
    Volume612
    Publication statusPublished - 2000
    MoE publication typeA4 Article in a conference publication
    EventMaterials, Technology and Reliability for Advanced Interconnetcs and Low-K Dielectrics - San Francisco, United States
    Duration: 23 Apr 200027 Apr 2000

    Conference

    ConferenceMaterials, Technology and Reliability for Advanced Interconnetcs and Low-K Dielectrics
    CountryUnited States
    CitySan Francisco
    Period23/04/200027/04/2000

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