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Analytical modeling of reservoir effect on electromigration in Cu interconnects

Published online by Cambridge University Press:  03 March 2011

Zhenghao Gan ,
A.M. Gusak ,
W. Shao ,
Zhong Chen ,
S.G. Mhaisalkar ,
T. Zaporozhets  and
K.N. Tu
Zhenghao Gan*
Affiliation:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
A.M. Gusak
Affiliation:
Department of Theoretical Physics, Cherkasy National University, Cherkasy 18017, Ukraine
W. Shao
Affiliation:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
Zhong Chen
Affiliation:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
S.G. Mhaisalkar
Affiliation:
School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798
T. Zaporozhets
Affiliation:
Department of Theoretical Physics, Cherkasy National University, Cherkasy 18017, Ukraine
K.N. Tu
Affiliation:
Department of Materials Science and Engineering, University of California–Los Angeles, Los Angeles, California 90095-1595
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

Electromigration (EM) in Cu dual-damascene interconnects with extensions (also described as overhangs or reservoirs) ranging from 0 to 120 nm in the upper metal (M2) was investigated by an analytical model considering the work of electron wind and surface/interface energy. It was found that there exists a critical extension length beyond which increasing extension lengths ceases to prolong electromigration lifetimes. The critical extension length is a function of void size and electrical field gradient. The analytical model agrees very well with existing experimental results. Some design guidelines for electromigration-resistant circuits could be generated by the model.

Keywords

CuDiffusionElectromigration
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 1 , January 2007 , pp. 152 - 156
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1Hu, C.K., Rosenberg, R., and Lee, K.L.: Electromigration path in Cu thin-film lines. Appl. Phys. Lett. 74, 2945 (1999).CrossRefGoogle Scholar
2Lloyd, J.R. and Clement, J.J.: Electromigration in copper conductors. Thin Solid Films 262, 135 (1995).CrossRefGoogle Scholar
3Vairagar, A.V., Mhaisalkar, S.G., Krishnamoorthy, A., Tu, K.N., Gusak, A.M., Meyer, M.A., and Zschech, E.: In situ observation of electromigration-induced void migration in dual-damascene Cu interconnect structures. Appl. Phys. Lett. 85, 2502 (2004).CrossRefGoogle Scholar
4Vairagar, A.V., Mhaisalkar, S.G., Krishnamoorthy, A., Meyer, M.A., Zschech, E., Tu, K.N., and Gusak, A.M.: Direct evidence of electromigration failure mechanism in dual-damascene Cu interconnect tree structures. Appl. Phys. Lett. 87, 081909 (2005).CrossRefGoogle Scholar
5Zaporozhets, T.V., Gusak, A.M., Tu, K.N., and Mhaisalkar, S.G.: Three-dimensional simulation of void migration at the interface between thin metallic film and dielectric under electromigration. J. Appl. Phys. 98, 103508 (2005).CrossRefGoogle Scholar
6Hu, C.K., Gignac, L., Rosenberg, R., Liniger, E., Rubino, J., Sambucetti, C., Domenicucci, A., Chen, X., and Stamper, A.K.: Reduced electromigration of Cu wires by surface coating. Appl. Phys. Lett. 81, 1782 (2002).CrossRefGoogle Scholar
7Hu, C.K., Gignac, L., Liniger, E., Herbst, B., Rath, D.L., Chen, S.T., Kaldor, S., Simon, A., and Tseng, W.T.: Comparison of Cu electromigration lifetime in Cu interconnects coated with various caps. Appl. Phys. Lett. 83, 869 (2003).CrossRefGoogle Scholar
8Shacham-Diamand, Y. and Lopatin, S.: High aspect ratio quarter-micron electroless copper integrated technology. Microelectron. Eng. 37–8, 77 (1997).CrossRefGoogle Scholar
9von Glasow, A., Fischer, A.H., Bunel, D., Friese, G., Hausmann, A., Heitzsch, O., Hommel, M., Kriz, J., Penka, S., Raffin, P., Robin, C., Sperlich, H.P., Ungar, F., and Zitzelsberger, A.E.: The influence of the SiN cap process on the electromigration and stressvoiding performance of dual damascene Cu interconnects. Proc 41st Annual Int. Rel. Phys. Symp., IEEE, Piscataway, NJ, 2003, p. 146.Google Scholar
10Yan, M.Y., Suh, J.O., Ren, F., Tu, K.N., Vairagar, A.V., Mhaisalkar, S.G., and Krishnamoorthy, A.: Effect of Cu3Sn coatings on electromigration lifetime improvement of Cu dual-damascene interconnects. Appl. Phys. Lett. 87, 211103 (2005).CrossRefGoogle Scholar
11Yan, M.Y., Tu, K.N., Vairagar, A.V., Mhaisalkar, S.G., and Krishnamoorthy, A.: Confinement of electromigration induced void propagation in Cu interconnect by a buried Ta diffusion barrier layer. Appl. Phys. Lett. 87, 261906 (2005).CrossRefGoogle Scholar
12Tu, K.N., Yeh, C.C., Liu, C.Y., and Chen, C.: Effect of current crowding on vacancy diffusion and void formation in electromigration. Appl. Phys. Lett. 76, 988 (2000).CrossRefGoogle Scholar
13Park, Y.B. and Jeon, I.S.: Effects of mechanical stress at no current stressed area on electromigration reliability of multilevel interconnects. Microelectron. Eng. 71, 76 (2004).CrossRefGoogle Scholar
14Jeon, I.S. and Park, Y.B.: Analysis of the reservoir effect on electromigration reliability. Microelectron. Reliab. 44, 917 (2004).CrossRefGoogle Scholar
15Shao, W., Vairagar, A.V., Tung, C.H., Xie, Z.L., Krishnamoorthy, A., and Mhaisalkar, S.G.: Electromigration in copper damascene interconnects: Reservoir effects and failure analysis. Surf. Coat. Technol. 198, 257 (2005).CrossRefGoogle Scholar
16Park, Y.J. and Thompson, C.V.: The effects of the stress dependence of atomic diffusivity on stress evolution due to electromigration. J. Appl. Phys. 82, 4277 (1997).CrossRefGoogle Scholar
17Matsumoto, T., Fujii, H., Ueda, T., Kamai, M., and Nogi, K.: Measurement of surface tension of molten copper using the free-fall oscillating drop method. Meas. Sci. Technol. 16, 432 (2005).CrossRefGoogle Scholar
18Loehman, R.E., Tomsia, A.P., Pask, J.A., and Johnson, S.M.: Bonding mechanisms in silicon-nitride brazing. J. Am. Ceram. Soc. 73, 552 (1990).CrossRefGoogle Scholar
19Gan, C.L., Thompson, C.V., Pey, K.L., and Choi, W.K.: Experimental characterization and modeling of the reliability of three-terminal dual-damascene Cu interconnect trees. J. Appl. Phys. 94, 1222 (2003).CrossRefGoogle Scholar