Skip to main content Accessibility help

Wafer Curvature Studies of Strengthening Mechanisms in Thin Films on Substrates

  • O. S. Leung (a1) and W. D. Nix (a1)


The effects of film thickness and passivation on plasticity of thin metal films on substrates have been studied using gold films as a model system. Wafer curvature/thermal cycling measurements were used to study plasticity in films ranging in thickness from 0.2 to 2.5 micrometers. We were able to describe these stress-temperature curves using a simple phenomenological model for linear kinematic hardening. The yield stresses revealed by the modeling were inversely proportional to the film thickness for thicknesses greater than about one micrometer. This relationship is expected from a dislocation model of plasticity. However, the residual stresses in thinner films are substantially lower than this relationship would predict and on unloading, these films show stress-temperature plots not predicted by the model. Stress-temperature curves were also measured after a tungsten passivation was deposited on the gold surface. Films thinner than one micrometer were substantially strengthened by this passivation and could then be described by the linear kinematic model. The observed stresses are only minimally affected for films thicker than about a micrometer. This strengthening effect on thinner films is consistent with the complete blocking of grain boundary diffusion near the free surface of the film.



Hide All
1 Venkatraman, R., Bravman, J. C., Nix, W. D., Davies, P. W., Flinn, P. A., and Fraser, D. B., J. Electron. Mater. (USA) p. 1231–7 (1990).
2 Nix, W. D., Metall.Trans. A, 20A, 2217–45 (1989).
3 Thompson, C. V., J. of Mater. Res. 8, 237–8 (1993).
4 Shen, Y. L., Suresh, S., He, M. Y, Bagchi, A., Kienzle, O., Ruhle, M., and Evans, A. G., J. Mater. Res. 13, 1928–37 (1998).
5 Kobrinsky, M. J. and Thompson, C. V., Appl. Phys. Lett. 73, 2429–31 (1998).
6 Gao, H., Zhang, L., Nix, W. D., Thompson, C. V., and Arzt, E., Acta Mater. 47, 2865–78 (1999).
7 Keller, R. M., Kuschke, W. M., Kretschmann, A., Bader, S., Vinci, R. P., Arzt, E., Filter, W. F., Rosenberg, R., Greer, A. L., and Gadepally, K., in Materials Reliability in Microelectronics V. Symposium, edited by Oates, A. S. (Mater. Res. Soc, Pittsburgh, PA, 1995), p. 309–14.
8 Keller, R. M., Sigle, W., Baker, S. P., Kraft, O., Arzt, E., Gao, H., and Sundgren, J. E., in Thin Films: Stresses and Mechanical Properties V I. Symposium, edited by Gerberich, W. W. (Mater. Res. Soc, Pittsburgh, PA, 1997), p. 221–6.
9 Thouless, M. D., Acta Metall. et Mater. 41, 1057–64 (1993).

Wafer Curvature Studies of Strengthening Mechanisms in Thin Films on Substrates

  • O. S. Leung (a1) and W. D. Nix (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed