Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-27T13:37:00.926Z Has data issue: false hasContentIssue false
  • English
  • Français

Effect of passivation on stress relaxation in electroplated copper films

Published online by Cambridge University Press:  01 June 2006

Dongwen Gan ,
Paul S. Ho ,
Yaoyu Pang ,
Rui Huang ,
Jihperng Leu ,
Jose Maiz  and
Tracey Scherban
Dongwen Gan
Affiliation:
Laboratory for Interconnect and Packaging, University of Texas, Austin, Texas 78712
Paul S. Ho
Affiliation:
Laboratory for Interconnect and Packaging, University of Texas, Austin, Texas 78712
Yaoyu Pang
Affiliation:
Department of Aerospace Engineering and Engineering Mechanics, University of Texas, Austin, Texas 78712
Rui Huang*
Affiliation:
Department of Aerospace Engineering and Engineering Mechanics, University of Texas, Austin, Texas 78712
Jihperng Leu
Affiliation:
Intel Corporation, Hillsboro, Oregon 97214
Jose Maiz
Affiliation:
Intel Corporation, Hillsboro, Oregon 97214
Tracey Scherban
Affiliation:
Intel Corporation, Hillsboro, Oregon 97214
*
a) Address all correspondence to this author. e-mail: ruihuang@mail.utexas.edu
Get access

Abstract

The present study investigated the effect of passivation on the kinetics of interfacial mass transport by measuring stress relaxation in electroplated Cu films with four different cap layers: SiN, SiC, SiCN, and a Co metal cap. Stress curves measured under thermal cycling showed different behaviors for the unpassivated and passivated Cu films, but were essentially indifferent for the films passivated with different cap layers. On the other hand, stress relaxation measured under an isothermal condition revealed clearly the effect of passivation, indicating that interface diffusion controls the kinetics of stress relaxation. The relaxation rates in the passivated Cu films were found to decrease in the order of SiC, SiCN, SiN, and metal caps. This correlates well with previous studies on the relationship between interfacial adhesion and electromigration. A kinetic model based on coupling of interface and grain-boundary diffusion was used to deduce the interface diffusivities and the corresponding activation energies.

Keywords

CuFilmKinetics
Type
Articles
Information
Journal of Materials Research , Volume 21 , Issue 6 , June 2006 , pp. 1512 - 1518
Copyright
Copyright © Materials Research Society 2006

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

REFERENCES

1.Hu, C.K., Rosenberg, R., Lee, K.Y.: Electromigration path in Cu thin film lines. Appl. Phys. Lett. 74, 2945 (1999).CrossRefGoogle Scholar
2.Besser, P., Marathe, A., Zhao, L., Herrick, M., Capasso, C., and Kawasaki, H.: Optimizing the electromigration performance of copper interconnects. IEDM Technical Digest (IEEE, Piscataway, NJ, 2000) p. 119.Google Scholar
3.Hu, C.K., Gignac, L., Rosenberg, R., Liniger, E., Rubino, J., Sambucetti, C., Domenicucci, A., Chen, X., Stamper, A.K.: Reduced electromigration of Cu wires by surface coating. Appl. Phys. Lett. 81, 1782 (2002).CrossRefGoogle Scholar
4.Lane, M.W., Liniger, E.G., Lloyd, J.R.: Relationship between interfacial adhesion and electromigration in Cu metallization. J. Appl. Phys. 93, 1417 (2003).CrossRefGoogle Scholar
5.Gan, D.W., Yoon, S., Ho, P.S., Leu, J., Maiz, J., and Scherban, T.: Correlation between stress relaxation and electromigration of Cu/low-k lines, in Proceedings of the Advanced Metallization Conference, Montreal, Canada, 2003, edited by Ray, G.W., Smy, T., Ohta, T., and Tsujimura, M. (Materials Research Society, Warrendale, PA, 2004), pp. 313–318.Google Scholar
6.Gan, D.W., Yoon, S., Ho, P.S., Cresta, P., Singh, N., Bower, A.F., Leu, J., and Shankar, S.: Effects of passivation layer on stress relaxation in Cu line structures, in Proceedings of the IEEE International Interconnect Technology Conference, San Francisco, June 2003, edited by Saraswat, K., Hayasaka, N., and Bartha, J. (IEEE, Piscataway, NJ, 2003), pp. 180–182.Google Scholar
7.Bower, A.F., Singh, N., Gan, D., Yoon, S., Ho, P.S., Leu, J., Shankar, S.: Numerical simulations and experimental measurements of stress relaxation by interface diffusion in a patterned copper interconnect structure. J. Appl. Phys. 97, 013539 (2005).Google Scholar
8.Gan, D.W., Huang, R., Ho, P.S., Leu, J., Maiz, J., and Scherban, T.: Effects of passivation layer on stress relaxation and mass transport in electroplated Cu films, in Proceedings of the 7th International Workshop on Stress-Induced Phenomena in Metallization, Austin, Texas, June 2004, edited by Ho, P.S., Baker, S.P., Nakamura, T., and Volkert, C.A. (AIP Conference Proceedings 741, Melville, NY, 2004), pp. 256–267.Google Scholar
9.Gan, D.W., Ho, P.S., Huang, R., Leu, J., Maiz, J., Scherban, T.: Isothermal stress relaxation in electroplated Cu films: Part I. Mass Transport Measurements. J. Appl. Phys. 97, 103531 (2005).CrossRefGoogle Scholar
10.Huang, R., Gan, D.W., Ho, P.S.: Isothermal stress relaxation in electroplated Cu films: Part II: Kinetic modeling. J. Appl. Phys. 97, 103532 (2005).CrossRefGoogle Scholar
11.Yeo, I-S. Thermal stress and stress relaxation in Al(Cu) interconnects. Ph.D. Dissertation, University of Texas, Austin, TX (1996).Google Scholar
12.Flinn, P.A.: Measurement and interpretation of stress in copper films as a function of thermal history. J. Mater. Res. 6, 1498 (1991).CrossRefGoogle Scholar
13.Thouless, M.D., Gupta, J., Harper, J.M.E.: Stress development and relaxation in copper films during thermal cycling. J. Mater. Res. 8, 1845 (1993).CrossRefGoogle Scholar
14.Vinci, R.P., Zielinski, E.M., Bravman, J.C.: Thermal strain and stress in copper films. Thin Solid Films 262, 142 (1995).CrossRefGoogle Scholar
15.Keller, R.M., Baker, S.P., Arzt, E.: Stress-temperature behavior of unpassivated thin copper films. Acta Mater. 47, 415 (1999).CrossRefGoogle Scholar
16.Weiss, D., Gao, H., Arzt, E.: Constrained diffusional creep in UHV-produced copper thin films. Acta Mater. 49, 2395 (2002).CrossRefGoogle Scholar
17.Thouless, M.D., Rodbell, K.P., Cabral, C. Jr.: Effect of a surface layer on the stress relaxation of thin films. J. Vac. Sci. Technol. A 14, 2454 (1996).CrossRefGoogle Scholar
18.Keller, R.M., Baker, S.P., Arzt, E.: Quantitative analysis of strengthening mechanisms in thin Cu films: Effects of film thickness, grain size, and passivation. J. Mater. Res. 13, 1307 (1998).CrossRefGoogle Scholar
19.Frost, H.J.: Deformation mechanisms in thin films, in Materials Reliability in Microelectronics II, edited by Thompson, C.V. and Lloyd, J.R. (Mater. Res. Soc. Symp. Proc. 265, Pittsburgh, PA, 1992), p. 3.Google Scholar
20.Lloyd, J.R., Lane, M.W., Liniger, E.G., Hu, C-K., Shaw, T.M., Rosenberg, R.: Electromigration and adhesion. IEEE Trans. Device Mater. Reliability 50, 113 (2005).CrossRefGoogle Scholar
21.Dehm, G., Weiss, D., Arzt, E.: In situ transmission-electron-microscopy study of therma-stress-induced dislocation in a thin Cu film constrained by a Si substrate. Mater. Sci. Eng. A 309–310, 468 (2001).CrossRefGoogle Scholar