Hostname: page-component-76fb5796d-22dnz Total loading time: 0 Render date: 2024-04-25T16:51:50.423Z Has data issue: false hasContentIssue false
  • English
  • Français

Microstructure evolution during electromigration in eutectic SnPb solder bumps

Published online by Cambridge University Press:  03 March 2011

C.M. Lu ,
T.L. Shao ,
C.J. Yang  and
Chih Chen
C.M. Lu
Affiliation:
National Chiao Tung University, Department of Material Science & Engineering, Hsin-chu 300 Taiwan, Republic of China
T.L. Shao
Affiliation:
National Chiao Tung University, Department of Material Science & Engineering, Hsin-chu 300 Taiwan, Republic of China
C.J. Yang
Affiliation:
National Chiao Tung University, Department of Material Science & Engineering, Hsin-chu 300 Taiwan, Republic of China
Chih Chen*
Affiliation:
National Chiao Tung University, Department of Material Science & Engineering, Hsin-chu 300 Taiwan, Republic of China
*
a)Address all correspondence to this author. e-mail: chih@cc.nctu.edu.tw
Get access

Abstract

A technique has been developed to facilitate analysis of the microstructural evolution of solder bumps after current stressing. Eutectic SnPb solders were connected to under-bump metallization (UBM) of Ti/Cr-Cu/Cu and pad metallization of Cu/Ni/Au. It was found that the Cu6Sn5 compounds on the cathode/chip side dissolved after the current stressing by 5 × 103 A/cm2 at 150 °C for 218 h. However, on the anode/chip side, they were transformed into (Nix,Cu1-x)3Sn4 in the center region of the UBM, and they were converted into (Cuy,Ni1-y)6Sn5 on the periphery of the UBM. For both cathode/substrate and anode/substrate ends, (Cuy,Ni1-y)6Sn5 compounds were transformed into (Nix,Cu1-x)3Sn4. In addition, the bumps failed at cathode/chip end due to serious damage of the UBM and the Al pad. A failure mechanism induced by electromigration is proposed in this paper.

Keywords

Phase transformationPackagingElectromigration
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 8 , August 2004 , pp. 2394 - 2401
Copyright
Copyright © Materials Research Society 2004

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.Tu, K.N.: Recent advances on electromigration in very-large-scale-integration of interconnects. J. Appl. Phys. 94, 5451 (2003).CrossRefGoogle Scholar
2.Tu, K.N. and Zeng, K.: Tin-lead (SnPb) solder reaction in flip chip technology. Mater. Sci. Eng. Rep. R34, 1 (2001).CrossRefGoogle Scholar
3.Brandenburg, S. and Yeh, S.: Electromigration studies of flip chip bump solder joints, Proceedings of Surface Mount International Conference and Exhibition, SM198, San Jose, CA, Aug. 23–27, 1998 (Edina, MN: SMTA, 1998), p. 337.Google Scholar
4.Wu, J.D., Zheng, P.J., and Kelly Lee, C.T.: Chiu, , and Lee, J.J.: Electromigration Failures of UBM/Bump Systems of Flip Chip Packages. 2002 Electronic Components and Technology Conference, p. 452.Google Scholar
5.Lee, T.Y., Tu, K.N., Kuo, S.M. and Frear, D.R.: Electromigration of eutectic SnPb solder interconnects for flip chip technology. J. Appl. Phys. 89 6, 3189 (2001).CrossRefGoogle Scholar
6.Jang, S.Y., Wolf, J., Kwon, W.S., and Paik, K.W.: UBM (under bump metallization) study for Pb-free electroplating bumping: Interface reaction and electromigration. 2002 Electronic Components and Technology Conference, p. 1213.Google Scholar
7.Ye, Hua: Cemal Basaran, and Douglas Hopkins: Thermomigration in Pb-Sn solder joints under joule heating during electric current stressing. Appl. Phys. Lett. 82, 7 (2003).CrossRefGoogle Scholar
8.Choi, W.J., Yeh, E.C.C., and Tu, K.N.: Electromigration of Flip Chip Solder Bump on Cu/Ni(V)/Al Thin Film Under Bump Metallization. 2002 Electronic Components and Technology Conference, p. 1201.Google Scholar
9.Chen, S.W., Chen, C.M. and Liu, W.C.: Electric current effects upon the Sn/Cu and Sn/Ni interfacial reactions. J. Electronic Mater. 27, 1193 (1998).CrossRefGoogle Scholar
10.Chen, W.T., Ho, C.E. and Kao, C.R.: Effect of Cu concentration on the interfacial reactions between Ni and Sn-Cu solders. J. Mater. Res. 17, 263 (2002).CrossRefGoogle Scholar
11.Mehrer, H. Reference database for diffusivities. (Landolt-Bönstein, New Series Group III, Vol. 26, Springer, Berlin, 1990).Google Scholar
12.Nah, J.W., Paik, K.W., Suh, J.O. and Tu, K.N.: Mechanism of electromigration-induced failure in the 97Pb–3Sn and 37Pb–63Sn composite solder joints. J. Appl. Phys. 94, 7560 (2003).CrossRefGoogle Scholar