Abstract
Interconnects containing bimodal grain size distributions are known to have lower me-dian times to electromigration-induced failure (MTTF). However, the deviation in the time to failure (DTTF) in such lines has not been well characterized. We find that Al-2%Cu-0.3%Cr interconnects with bimodally distributed grain sizes have MTTF’s which are more than an order of magnitude lower than lines with monomodally distributed small grain sizes. However, the DTTF’s for both types of lines are similar, and in fact slightly lower for lines with bimodal structures. An activation energy of 0.85 eV was obtained both for lines with monomodal large grain structures and bimodal grain struc-tures, suggesting that grain boundary diffusion is the controlling mechanism in both cases. A model based simply on microstructural characteristics,e.g. the distribution of the number of grain boundaries, can explain the lower MTTF’s and DTTF’s for lines with bimodal structures. The implications of bimodal grain size distributions on the reliability of large numbers of lines are discussed. Also, a new, convenient graphical tool for illustrating the failure rate of interconnects with lognormally distributed failure times is presented.
Similar content being viewed by others
References
F. d’Heurle and R. Rosenberg, “Electromigration in Thin Films,” in G. Hass, M. Francombe, and R. Hoffman, eds., Physics of Thin Films, Vol. 7, Academic, New York, 1973, p. 257.
M. J. Attardo and R. Rosenberg, J. Appl. Phys.41, 2381 (1970).
Y. E. Strausser, B. L. Euzent, R. C. Smith, B. M. Tracy, and K. Wu, 25th Annual Proc. Int. Reliability Physics Symp., IEEE, p. 140, 1987.
J. Cho and C. V. Thompson, Appl. Phys. Lett.54, 2577 (1989).
A. Gangulee and F. M. d’Heurle, Thin Solid Films12, 399 (1972).
C. V. Thompson and C. D. Maiorino, in 18th Int. Conf. on Solid State Devices and Mater. Jpn Soc. Applied Physics, Tokyo, p. 491, 1986.
C. V. Thompson and J. Cho, IEEE Trans. Electron Devices Lett.EDL-7, 667 (1986).
J. M. Towner, Solid State Technol. Oct., 197 (1984).
M. J. Attardo, R. Rutledge and R. C. Jack, J. Appl. Phys.42, 4343 (1971).
P. Bratley, B. L. Fox and L. E. Schrage, A Guide to Simulation, Springer-Verlag, New York, 1983, p. 135.
H. H. Hoang, E. L. Nikkei, J. M. McDavid and R. B. MacNaughton, J. Appl. Phys.65, 1044 (1989).
L. R. Goldthwaite, Proc. 7th National Symp. Reliability and Quality Control, 1961, p. 208.
W. J. Bertram, “Yield and Reliability,” in S. M. Sze, ed., VLSI Technol. McGraw-Hill, New York, 1983.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Cho, J., Thompson, C.V. Electromigration-induced failures in interconnects with bimodal grain size distributions. J. Electron. Mater. 19, 1207–1212 (1990). https://doi.org/10.1007/BF02673334
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02673334