6. Diffusion Barriers

  1. Mikhail R. Baklanov2,
  2. Paul S. Ho3 and
  3. Ehrenfried Zschech4
  1. Michael Hecker1 and
  2. René Hübner4

Published Online: 17 FEB 2012

DOI: 10.1002/9781119963677.ch6

Advanced Interconnects for ULSI Technology

Advanced Interconnects for ULSI Technology

How to Cite

Hecker, M. and Hübner, R. (2012) Diffusion Barriers, in Advanced Interconnects for ULSI Technology (eds M. R. Baklanov, P. S. Ho and E. Zschech), John Wiley & Sons, Ltd, Chichester, UK. doi: 10.1002/9781119963677.ch6

Editor Information

  1. 2

    IMEC, Kapeldreef 75, B-3001 Leuven, Belgium

  2. 3

    Lab for Interconnect and Packaging, The University of Texas at Austin, UT-PRC 10100 Burnet Road, Bldg 160, Mail Code R8650, Austin, TX 78758, USA

  3. 4

    Fraunhofer Institute for Non-Destructive Testing IZFP, Dresden Branch, Maria-Reiche-Strasse 2, 01109 Dresden, Germany

Author Information

  1. 1

    Center for Complex Analysis, GLOBALFOUNDRIES Dresden Module One LLC & Co. KG, Wilschdorfer Landstrasse 101, 01109 Dresden, Germany

  2. 4

    Fraunhofer Institute for Non-Destructive Testing IZFP, Dresden Branch, Maria-Reiche-Strasse 2, 01109 Dresden, Germany

Publication History

  1. Published Online: 17 FEB 2012
  2. Published Print: 24 FEB 2012

ISBN Information

Print ISBN: 9780470662540

Online ISBN: 9781119963677

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Keywords:

  • diffusion barriers;
  • Cu interconnects;
  • Cu metallization;
  • plating;
  • thin films;
  • metal-based barriers;
  • nanolayers

Summary

The utilization of copper as an interconnect material requires application of barrier films in order to prevent outdiffusion of copper into surrounding materials and to obtain desired electrical and mechanical parameters of the interconnects. In this chapter, the properties of different types of barrier films suited for present and future CMOS technology nodes are discussed. Apart from their material, interface and microstructural properties, deposition and characterization techniques are also discussed in detail. After reviewing properties of widely used refractory-metal barriers, such as those based on Ta, W and Ti, including various stacks and composites of these and other metal-consisting barriers, the focus is on advanced barrier systems. Examples are Ru-based films enabling direct Cu plating and systems possessing improved reliability properties as obtained for interconnects with CoWP-based cap films or self-forming barriers on the basis of Cu(Mn) alloys. Approaches to obtain conformal diffusion barriers with thicknesses significantly below 5 nm, such as self-assembled molecular nanolayers and polymer-based barriers, are also discussed. A key for successful development of future barrier systems will be a detailed understanding of their properties and defect mechanisms on the nanoscale.