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Initial hillock formation and changes in overall stress in Al–Cu films and pure Al films during heating

Published online by Cambridge University Press:  31 January 2011

C. Kylner  and
L. Mattsson
C. Kylner
Affiliation:
Department of Physics II (Optics), Royal Institute of Technology, SE-100 44 Stockholm, Sweden, and Surface Evaluation Laboratory, Institute of Optical Research, Electrum 236, SE-164 40 Kista, Sweden
L. Mattsson
Affiliation:
Surface Evaluation Laboratory, Institute of Optical Research, Electrum 236, SE-164 40 Kista, Sweden and Department of Materials Processing Technology (Industrial Metrology and Optics), Royal Institute of Technology, SE-100 44 Stockholm, Sweden
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Abstract

The effect of adding a few percent (3 at.%) Cu to Al films on the initial hillock formation and the changes in overall film stress were studied. Al films were evaporated by an electron-beam gun onto Si wafers in an ultrahigh vacuum deposition system and Al–Cu films were coevaporated with a thermally heated source used for the Cu. The as-deposited samples were radiatively heated at 3 °C/s in an air environment. During heating, the initial hillocking and the changes in overall stress were measured simultaneously and in real time with a specially designed optical instrument. The measurement principle of this instrument is based on laser beam deflection, caused by wafer bending due to film stress, and collection of the laser light scattered off from the hillocks appearing on the film surface. The experimental results show that Cu alloying has a strengthening effect on Al films, resulting in delayed and considerably reduced hillock formation. Before heating, the as-deposited Al–Cu samples were investigated by total integrated scattering and atomic force microscopy. These investigations showed that Al–Cu films are considerably smoother and have smaller grains than Al films of similar thickness (340 nm). It was found that the small grains of Al–Cu films contribute to increasing the tensile stress–temperature slope. In addition, Al–Cu films can withstand higher compressive stresses than Al films.

Type
Articles
Information
Journal of Materials Research , Volume 14 , Issue 10 , October 1999 , pp. 4087 - 4092
Copyright
Copyright © Materials Research Society 1999

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References

REFERENCES

1.Ames, I., d'Heurle, F.M., and Horstmann, R.E., IBM J. Res. Dev. 14, 461 (1970).Google Scholar
2.Martin, B.C., Tracy, C.J., Mayer, J.W., and Hendrickson, L.E., Thin Solid Films 271, 64 (1995).CrossRefGoogle Scholar
3.Kylner, C. and Mattsson, L., Thin Solid Films 348, 222 (1998).Google Scholar
4.Jackson, M.S. and Li, C-Y., Acta Metall. Mater. 30, 1993 (1982).Google Scholar
5.Schwarzer, R.A. and Gerth, D., J. Electron Mater. 22(6), 607 (1993).Google Scholar
6.Gerth, D., Katzer, D., and Krohn, M., Thin Solid Films 208, 67 (1992).Google Scholar
7.Koleshko, V.M., Belitsky, V.F., and Kiryushin, I.V., Thin Solid Films 142, 199 (1986).Google Scholar
8.Binary Alloy Phase Diagrams, edited by Massalski, T.B. (ASM, Materials Park, OH, 1993).Google Scholar
9.Frear, D.R., Sanchez, J.E., Romig, A.D., and Morris, J.W. Jr, Metall. Mater. Trans. A, 21, 2449 (1990).Google Scholar
10.Philofsky, E., Ravi, K., Hall, E., and Black, J., Ninth International Annual Reliability Physics Symposium (IEEE, New York, 1971), pp. 120–128.Google Scholar
11.Doerner, M.F. and Nix, W.D., Crit. Rev. Solid State Mater. Sci. 14(3), 225 (1988).CrossRefGoogle Scholar
12.Iwamura, E., Ohnishi, T., and Yoshikawa, K., Thin Solid Films 270, 450 (1995).Google Scholar
13.Thouless, M.D., Gupta, J., and Harper, J.M.E, J. Mater. Res. 8, 1845 (1993).CrossRefGoogle Scholar
14.Nix, W.D., Metall. Mater. Trans. A 20, 2217 (1989).Google Scholar
15.Sinha, A.K., Levinstein, H.J., and Smith, T.E., J. Appl. Phys. 49(4), 2423 (1978).Google Scholar
16.Flinn, P.A., Gardner, D.S., and Nix, W.D., IEEE Trans. Electron Devices ED-34(3), 689 (1987).Google Scholar
17.Flinn, P.A., in Thin Films: Stresses and Mechanical Properties Symposium, edited by Bravman, J.C., Nix, W.D., Barnett, D.M., and Smith, D.A. (Mater. Res. Soc. Symp. Proc. 130, Pittsburgh, PA, 1989), pp. 41–51.Google Scholar
18.Hershkovitz, M., Blech, I.A., and Komem, Y., Thin Solid Films 130, 87 (1985).Google Scholar
19.Gardner, D.S. and Flinn, P.A., IEEE Trans. Electron Devices, 35(12), 2160 (1988).Google Scholar
20.Mattsson, L., Le Page, Y-H., and Ericsson, F., Thin Solid Films 198, 149 (1991).Google Scholar
21.Kylner, C. and Mattsson, L., Thin Solid Films 307, 169 (1997).CrossRefGoogle Scholar
22.Kylner, C. and Mattsson, L., Rev. Sci. Instrum. 68(1), 143 (1997).Google Scholar
23.Kylner, C. and Mattsson, L., in Thin Films: Stresses and Mechanical Properties VI, edited by Gerberich, M.W., Gao, H., Sundgren, J-E., and Baker, S.P. (Mater. Res. Soc. Symp. Proc. 436, Pittsburgh, PA, 1997), pp. 257–262.Google Scholar
24.Kylner, C. and Mattsson, L., J. Mater. Res. 13, 1666 (1998).Google Scholar
25.Mattsson, L., in Thin Film Technologies, edited by Jacobsson, J.R. (Proc. SPIE—The International Society for Optical Engineering, Washington, DC, 1986), pp. 264–271.Google Scholar
26.Standard Test Method for Measuring the Effective Surface Roughness of Optical Components by Total Integrated Scattering, Standard F 1048–87 (American Society for Testing and Materials, West Conshohocken, PA, 1987).Google Scholar
27.Hansen, M., Constitution of Binary Alloys (McGraw-Hill, New York, 1965).Google Scholar
28.Murray, J.L., Int. Metals Rev. 30(5), 211 (1985).Google Scholar
29.Stoney, G.G., Proc. R. Soc. London, Ser. A 82, 172 (1909).Google Scholar
30.Doerner, M.F., Gardner, D.S., and Nix, W.D., J. Mater. Res. 1, 845 (1986).Google Scholar