Hostname: page-component-848d4c4894-v5vhk Total loading time: 0 Render date: 2024-06-17T05:19:21.315Z Has data issue: false hasContentIssue false

A1/A1-Oxide Interface Diffusion During Electromigration

Published online by Cambridge University Press:  15 February 2011

R.A. Augur
Affiliation:
Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA, Eindhoven, The Netherlands.
R.A.M. Wolters
Affiliation:
Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA, Eindhoven, The Netherlands.
W. Schmidt
Affiliation:
Philips Semiconductors, Stresemannallee 101, D2000 Hamburg 54, Germany.
S. Kordić
Affiliation:
Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA, Eindhoven, The Netherlands.
Get access

Abstract

This paper presents new results concerning diffusion at the interface between Al and its oxide, due to electromigration in Al interconnects. The results show that the phenomenon is an important and general one. Significant large-scale modification of the surface of Alalloy conductors was observed after electromigration stress under a wide range of different conditions: 1) in a number of different alloys (Al-Si, Al-Cu, Al-Si-V & Al-Si-V-Pd), 2) with and without passivation, 3) over an extended temperature range, 4) over an extended range of current density, and 5) with a number of different underlayers (SiO2, W-Ti (no vacuum-break before Al deposition) and W-Ti (oxidized surface before Al deposition)). After electromigration stressing, the surface showed height variations: at certain locations the original thickness remained, while at adjacent locations the thickness was reduced; as much as 150nm in 2500 hrs, for Al-Si on oxidized W-Ti metallization. Damage by thinning has received little attention in the past. Based on the results presented, a model for the underlying mechanism is proposed. In this model Al atoms diffuse concurrently along the interface between the Al-metal and its oxide, and through the grain boundaries, even at low stress conditions and in non-bamboo lines.

Type
Research Article
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 Rosenberg, R. Vac, J.. Sci. & Tech., 9, 263 (1972).Google Scholar
2 Rosenberg, R. and Ohring, M., J. Appl. Phys., 42, 5671 (1971).Google Scholar
3 Vaidya, S. and Sinha, A.K., Thin Solid Films, 75, 253 (1981).Google Scholar
4 Ho, P.S. and Kwok, T., Rep. Prog. Phys., 52, 301 (1989).Google Scholar
5 Kinsbron, E., Appl. Phys. Lett., 36, 968 (1980).Google Scholar
6 Cho, J. and Thompson, C.V., Appl. Phys. Lett., 54, 2577 (1989).Google Scholar
7 Thompson, C.V. and Lloyd, J.R., MRS Bulletin, Dec. 1993, p.19.Google Scholar
8 Longworth, H.P. and Thompson, C.V., Materials Reliability Issues in Microelectronics II, edited by Thompsom, C.V. and Lloyd, J.R. (Mater. Res. Soc. Proc. 265, Pittsburgh, PA, 1992) pp.95100.Google Scholar
9 Hu, C.-K., Small, M.B., Rodbell, K.P., Blauner, P. and Ho, P.S., J. Appl. Phys., 62, 1023 (1993).Google Scholar
10 Lloyd, J.R., Materials Reliability Issues in Microelectronics IV, edited by Børgesen, P., Coburn, J.C., Sanchez, J.E. Jr., Rodbell, K.P. and Filter, W.F. (Mater. Res. Soc. Proc. 338, Pittsburgh, PA, 1994) pp.367372.Google Scholar
11 Joo, Y.-C. and Thompson, C.V.,Materials Reliability Issues in Microelectronics pp.319–24.Google Scholar
12 Augur, R.A., Procs. 32nd International Reliability Physics Symposium (IEEE, San Fransisco, CA, 1994) pp. 266–73.Google Scholar
13 Black, J.R., IEEE Trans. Elec. Devs., ED-16, 338 (1969).Google Scholar
14 Thomas, R.W. and Calabrese, D.W., Procs. 21st International Reliability Physics Symposium, (IEEE, Phoenix, AZ, 1983) pp. 19.Google Scholar
15 Levine, E. and Kitcher, J., Procs. 22nd International Reliability Physics Symposium, (IEEE, Las Vegas, 1984) pp. 242–9 [Conclusion 4.].Google Scholar
16 Devaney, J.R., Procs. 8th International Reliability Physics Symposium (IEEE, Las Vegas, 1970) pp. 128–32.Google Scholar
17 Blech, I.A. and Meieren, E.S., J. Appl. Phys., 40, 485 (1969).Google Scholar
18 Chang, C.Y. and Vook, R.W., Materials Reliability Issues in Microelectronics I, edited by Lloyd, J.R., Yost, F.G. and Ho, P.S. (Mater. Res. Soc. Proc. 225, Pittsburgh, PA, 1991) pp.125129.Google Scholar
19 Dirks, A.G., Augur, R.A., Kordić, S. and Wolters, R.A.M., Advanced Metallizations for Devices and Circuits - Science, Technology and Manufacturability, edited by Murarka, S.P., Katz, A., Tu, K.N. and Maex, K. (Mater. Res. Soc. Proc. 337, Pittsburgh, PA, 1994) pp.237248.Google Scholar