Hostname: page-component-848d4c4894-jbqgn Total loading time: 0 Render date: 2024-07-06T02:33:21.402Z Has data issue: false hasContentIssue false
  • English
  • Français

The Effect of Cu Distribution on Post-Patterning Grain Growth and Reliability of Al-1%Cu Interconnects

Published online by Cambridge University Press:  15 February 2011

B. D. Knowlton ,
R. I. Frank  and
C. V. Thompson
B. D. Knowlton
Affiliation:
Massachusetts Institute of Technology, Cambridge, MA 02139
R. I. Frank
Affiliation:
Massachusetts Institute of Technology, Cambridge, MA 02139
C. V. Thompson
Affiliation:
Massachusetts Institute of Technology, Cambridge, MA 02139
Get access

Abstract

The reliability of Al-Cu interconnects is a strong function of both grain structure and the Cu content and distribution. Because pre-patteming and post-patterning grain growth are affected by the presence of Al2Cu precipitates, the effects of grain structure and Cu distribution are interrelated. We have studied the effect of Al2Cu precipitate spacing on interconnect reliability independent of grain size effects. This was accomplished by varying the thermal history of the continuous films to produce samples with identical grain structures, but different precipitate spacings. The precipitate spacing in continuous films was varied by an order of magnitude, from 2.6 μm to 25. pm. Lines were then patterned from each sample and tested. Lifetime testing results show that the reliability of lines with smaller precipitate spacings can be roughly an order of magnitude higher than that of lines with a larger precipitate spacing. We have also qualitatively studied the effects of Cu distribution on post-patterning grain growth. We found that precipitates retard post-patterning grain evolution, leading to reduced reliability. These results suggest strategies for developing thermal histories which will lead to optimal reliability.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 391: Symposium T – Materials Reliability in Microelectronics V , 1995 , 361
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Ho, P. S. and Lewis, J. E., Thin Solid Films 25, no. 2, 301–315 (1975).Google Scholar
2 Thompson, C. V., Grain Growth in Thin Films, Annual Review of Materials Science 20, 245 (1990).Google Scholar
3 Cho, J., Effect of Microstructure of Aluminum Alloys on the Electromigration Limited Reliability of VLSI Interconnects, Ph.D. Thesis, MIT Department of Materials Science and Engineering (1990).Google Scholar
4 Thompson, C. V. and Kahn, H., J. of Electron. Mat. 22, p. 581 (1993).Google Scholar
5 Press, W. H., Fleming, B. P., Teukolsky, S. A., and Vetterling, W. J., Numerical Recipes, (Cambridge University Press, Cambridge, 1986), pp. 155–192.Google Scholar
6 Knowlton, B. D. and Thompson, C. V., unpublished research.Google Scholar