Electromigration-induced strain relaxation in Cu conductor lines

Abstract

Strain evolution in 0.45-μm-thick, 2-μm-wide, and 100-μm-long Cu conductor lines with a passivation layer has been investigated using synchrotron x-ray microdiffraction. A moderate electromigration-current density of 2.2 × 105 A/cm2 was used to minimize Joule heating in the Cu conductor lines. After 120 h of current flowing in the Cu lines at 270 °C, measurements show strain relaxation and homogenization occurring in the Cu lines with current flowing, but not in Cu conductor lines without current. Stronger interaction between electrons with Cu atoms in areas with higher strains was proposed to explain the observation.

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References

  1. 1.

    H.B. Huntington and A.R. Grone: Current-induced marker motion in gold wires. Phys. Chem. Solids 20, 76 (1961).

    CAS  Article  Google Scholar 

  2. 2.

    C.S. Hau-Riege: An introduction to Cu electromigration. Microelectron. Reliab. 44, 195 (2004).

    CAS  Article  Google Scholar 

  3. 3.

    V. Sukharev and E. Zschech: A model for electromigration-induced degradation mechanisms in dual-inlaid copper interconnects: Effect of interface bonding strength. J. Appl. Phys. 96, 6337 (2004).

    CAS  Article  Google Scholar 

  4. 4.

    C-K. Hu, L. Gignac, E. Liniger, B. Herbst, D.L. Rath, S.T. Chen, S. Kaldor, A. Simon, and W-T. Tseng: Comparison of Cu electromigration lifetime in Cu interconnects coated with various caps. Appl. Phys. Lett. 83, 869 (2003).

    CAS  Article  Google Scholar 

  5. 5.

    G.S. Cargill III: Microdiffraction and microfluorescence studies of electromigration-induced stresses and composition changes. AIP Conf. Proc. 612, 193 (2002).

    CAS  Article  Google Scholar 

  6. 6.

    G.E. Ice and B.C. Larson: 3D x-ray crystal microscope. Adv. Eng. Mater. 2, 643 (2000).

    CAS  Article  Google Scholar 

  7. 7.

    H. Zhang, G.S. Cargill III, Y. Ge, A.M. Maniatty, and W. Liu: Strain evolution in Al conductor lines during electromigration. J. Appl. Phys. 104, 123533 (2008).

    Article  Google Scholar 

  8. 8.

    P.-C. Wang, G.S. Cargill III, I.C. Noyan, and C-K. Hu: Electromigration-induced stress in aluminum conductor lines measured by x-ray microdiffraction. Appl. Phys. Lett. 72, 1296 (1998).

    CAS  Article  Google Scholar 

  9. 9.

    B.C. Valek, J.C. Bravman, N. Tamura, A.A. MacDowell, R.S. Celestre, H.A. Padmore, R. Spolenak, W.L. Brown, B.W. Batterman, and J.R. Patel: Electromigration-induced plastic deformation in passivated metal lines. Appl. Phys. Lett. 81, 4168 (2002).

    CAS  Article  Google Scholar 

  10. 10.

    I.A. Blech: Electromigration in thin aluminum films on titanium nitride. J. Appl. Phys. 47, 1203 (1976).

    CAS  Article  Google Scholar 

  11. 11.

    A.S. Budiman, W.D. Nix, N. Tamura, B.C. Valek, K. Gadre, J. Maiz, and J.R. Patel: Crystal plasticity in Cu damascene interconnect lines undergoing electromigration as revealed by synchrotron x-ray microdiffraction. Appl. Phys. Lett. 88, 233515 (2006).

    Article  Google Scholar 

  12. 12.

    J.-S. Chung and G.E. Ice: Automated indexing for texture and strain measurement with broad-bandpass x-ray microbeams. J. Appl. Phys. 86, 5249 (1999).

    CAS  Article  Google Scholar 

  13. 13.

    E. Kreyszig: Advanced Engineering Mathematics, 8th ed. (John Wiley & Sons, Inc., 1999), p. 1110.

    Google Scholar 

  14. 14.

    H. Conrad and A.F. Sprecher: Dislocations in Solids, edited by F.R.N. Nabarro (Elsevier Science Publications BV, 1989), p. 497.

  15. 15.

    E.E. Vdovin and A.Yu. Kasumov: Direct observation of electrotransport of dislocations in a metal. Sov. Phys. Solid State 30, 180 (1988).

    Google Scholar 

  16. 16.

    W.D. Callister Jr.: Materials Science and Engineering: An Introduction (John Wiley & Sons, 2003).

    Google Scholar 

  17. 17.

    L.E. Moyer, G.S. Cargill III, W. Yang, B.C. Larson, and G.E. Ice: X-ray microbeam diffraction measurements in polycrystalline aluminum and copper thin films, in Thin Films—Stresses and Mechanical Properties X, edited by S.G. Corcoran, Y.-C. Joo, N.R. Moody, and Z. Suo (Mater. Res. Soc. Symp. Proc. 795, Warrendale, PA, 2004), U1.7, p. 15.

    CAS  Google Scholar 

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Acknowledgments

The authors of this study thank Dr. C-K. Hu at the IBM T.J. Watson Research Center for useful guidance and for providing the Cu conductor line samples. Dr. W. Liu from Argonne National Laboratory provided valuable assistance with the synchrotron x-ray microdiffraction measurements and data analysis.

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Correspondence to H. Zhang.

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Zhang, H., Cargill, G. Electromigration-induced strain relaxation in Cu conductor lines. Journal of Materials Research 26, 498–502 (2011). https://doi.org/10.1557/jmr.2011.2

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