Hostname: page-component-84b7d79bbc-l82ql Total loading time: 0 Render date: 2024-07-26T19:40:44.608Z Has data issue: false hasContentIssue false
  • English
  • Français

Determination of the Effects of Strain on Electrical Resistivity in Patterned Interconnects

Published online by Cambridge University Press:  10 February 2011

John E. Sanchez Jr.  and
Christopher J. Reilly
John E. Sanchez Jr.
Affiliation:
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109
Christopher J. Reilly
Affiliation:
Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109
Get access

Abstract

Sensitive measurements of electromigration-induced resistance changes in metallization interconnects have been previously interpreted as due to precipitation effects, vacancy concentration changes and local stress changes (due to the piezoresistance effect). The latter have the potential for characterizing the early stages of electromigration-induced diffusive phenomena prior to larger scale effects such as voiding and subsequent localized joule heating which seriously complicate the interpretation of small resistance changes. However the utility of such “early" measurements is also hindered by lack of an accurate knowledge of the stress coefficient of resistivity as a proper characterization of the change in strain state of the Al. We present measurements of the effects of volumetric strain on the resistivity of Al interconnects where the strain is induced by thermal expansion mismatch between the Al and surrounding passivations. The piezoresistance effect is characterized by properly accounting for the degree of interconnect constraint (and volumetric strain) induced by thermal expansion mismatch as a function of temperature for both passivated and unpassivated lines. Sensitive interconnect resistance versus temperature measurements for differently constrained interconnects (with different volumetric strains) thus allows for the measurement of the piezoresistance effect. Other effects such as solute or vacancy concentration changes with temperature are minimized since the measurements are performed by cooling the passivated and unpassivated lines from room temperature to approximately 70K, rather than by significant heating above room temperature. We determine the piezoresistance coefficient, defined as dρ/dɛv, where ρ = resistivity and ɛv = volumetric strain, to be approximately 1.5−5 Ω-cm, in rough agreement with previous work. The interpretation of sensitive resistance measurements as volumetric strains in isolated sections of interconnects undergoing electromigration-induced diffusion processes is described for specialized test structures.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 516: Symposium E – Low Dielectric Constant Materials IV , January 1998 , 219
Copyright
Copyright © Materials Research Society 1998

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.) Sanchez, J. Jr., and Pham, V. in Materials Reliability in Microelectronics IV, edited by Borgesen, P. et al. (Mater. Res. Soc. Proc. 338, Pittsburgh, PA, 1994) p. 459–464.Google Scholar
2.) Blech, I. A. and Herring, C., Applied Physics Letters, 29, p. 131–133 (1976).10.1063/1.89024Google Scholar
3.) Korhonen, M. A., Borgesen, P., Tu, K. N., Li, C.-Y., J. Appl. Phys., 73, p. 3790 (1993).Google Scholar
4.) Thouless, M. D., Yu, H., Zhao, Z. and Yang, W., J. Mech. Phys. Solids, 41, p. 371 (1996).10.1016/0022-5096(95)00077-1Google Scholar
5.) Brown, D., Sanchez, J., Korhonen, M. and Li, C.-Y., Appl. Phys. Lett., 67, p. 439 (1995).10.1063/1.114625Google Scholar
6.) Kraayeveld, J., Verbruggen, A. and Willemsen, A., Appl. Phys. Lett, 67, p. 1226 (1995).10.1063/1.115015Google Scholar
8.) Kim, C., Selitser, S. I. and Morris, J.W. Jr., J. Appl. Phys., 75, p.879–884 (1994)10.1063/1.356442Google Scholar
9.) Scorzoni, A., De Munari, I., Stulens, H., D'Haeger, V. in Materials Reliability in Microelectronics V edited by Oates, A. S., Filter, W., Rosenberg, R., Greer, A. L. and Gadepally, K. (Mater. Res. Soc. Proc. 391, Pittsburgh, PA, 1995) p. 513–519.Google Scholar
10.) Alers, G.B, Oates, A.S. and Beverly, N.L., Appl. Phys. Lett, 66, p. 3600 (1995).Google Scholar
11.) Beverly, N.L., Alers, G.B and Prybala, J. A., Appl. Phys. Lett, 68, p.2372 (1995).Google Scholar
12.) Lawson, A.W., Progress in Metal Physics, 6, 1 (1956).Google Scholar
13.) Verbruggen, A. H. et al. in Materials Reliability in Microelectronics VII, edited Clement, J. et al. (Mater. Res. Soc. Proc. 473, Pittsburgh, PA, 1997) p. 255–266.Google Scholar
14.) Alers, G.B, Beverly, N.L. and Oates, A.S., J. Appl, Phys., 79, p. 7598–7603 (1996).Google Scholar
15.) Sauter, A. I. and Nix, W. D. in Thin Films: Stresses and Mechanical Properties II, edited Doerner, M. et al. (Mater. Res. Soc. Proc. 188, Pittsburgh, PA, 1990) p. 15–20.Google Scholar
16.) Kedves, F. J., Gergelly, L., Hordos, M. and Kovac-Csentenyi, E., Physica Status Solidi (a), 13, p. 685 (1972).Google Scholar
17.) Ghosh, S. K. et al. in Proc. 10th VLSI Multilevel Interconnect Conference, edited by Wade, V. (VMIC-1993, Santa Clara, CA, 1993) p. 332–334.Google Scholar
18.) Besser, P. R., Mack, A. S., Fraser, D. and Bravman, J. C., J. Electrochem. Soc., 140, p. 1769–1772 (1993).Google Scholar
19.) Greenebaum, B. et al. , Appl. Phys. Lett., 58, p. 1845 (1991).Google Scholar