Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-28T09:14:28.808Z Has data issue: false hasContentIssue false
  • English
  • Français

Cross interactions on interfacial compound formation of solder bumps and metallization layers during reflow

Published online by Cambridge University Press:  01 December 2004

T.L. Shao ,
T.S. Chen ,
Y.M. Huang  and
Chih Chen
T.L. Shao
Affiliation:
National Chiao Tung University, Department of Material Science & Engineering, Hsin-chu 300 Taiwan, Republic of China
T.S. Chen
Affiliation:
National Chiao Tung University, Department of Material Science & Engineering, Hsin-chu 300 Taiwan, Republic of China
Y.M. Huang
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: [email protected]
Get access

Abstract

While the dimension of solder bumps keeps shrinking to meet higher performance requirements, the formation of interfacial compounds may be affected more profoundly by the other side of metallization layer due to a smaller bump height. In this study, cross interactions on the formation of intermetallic compounds (IMCs) were investigated in eutectic SnPb, SnAg3.5, SnAg3.8Cu0.7, and SnSb5 solders jointed to Cu/Cr–Cu/Ti on the chip side and Au/Ni metallization on the substrate side. It is found that the Cu atoms on the chip side diffused to the substrate side to form (Cux,Ni1−x)6Sn5 or (Niy,Cu1−y)3Sn4 for the four solders during the reflow for joining flip chip packages. For the SnPb solder, Au atoms were observed on the chip side after the reflow, yet few Ni atoms were detected on the chip side. In addition, for SnAg3.5 and SnSn5 solders, the Ni atoms on the substrate side migrated to the chip side during the reflow to change binary Cu6Sn5 into ternary (Cux,Ni1−x)6Sn5 IMCs, in which the Ni weighed approximately 21%. Furthermore, it is intriguing that no Ni atoms were detected on the chip side of the SnAg3.8Cu0.7 joint. The possible driving forces responsible for the diffusion of Au, Ni, and Cu atoms are discussed in this paper.

Keywords

PackagingPhase transformationDiffusion
Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 12 , December 2004 , pp. 3654 - 3664
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

1Miller, L.F.: Controlled collapse reflow chip joining. IBM J. Res. Develop. 13, 239 (1969).CrossRefGoogle Scholar
2Totta, P.A. and Sopher, R.P.: SLT device metallurgy and its monolithic extensions. IBM J. Res. Develop. 13, 226 (1969).CrossRefGoogle Scholar
3Tu, K.N. and Zeng, K.: Sn-Pb solder reaction in flip chip technology. Mater. Sci. Eng. Rep. R 34, 1 (2001).CrossRefGoogle Scholar
4Frear, D.R., Jang, J.W., Lin, J.K. and Zhang, C.: Pb-free solders for flip-chip interconnects. JOM 53, 28 (2001).CrossRefGoogle Scholar
5Seelig, K. and Suraski, D.: The status of lead-free solders, in Lead-Free Soldering Technology, edited by IEEE Components, Packaging, and Manufacturing Technology Society (Proc. of the 50th Electronic Components and Technology Conference, Las Vegas, NV, 2000) p. 1405.Google Scholar
6Kim, H.K., Liou, H.K. and Tu, K.N.: Three-dimensional morphology of a very rough interface formed in the soldering reaction between eutectic SnPb and Cu. Appl. Phys. Lett. 66, 2337 (1995).CrossRefGoogle Scholar
7Kim, P.G., Jang, J.W., Lee, T.Y. and Tu, K.N.: Interfacial reaction and wetting behavior in eutectic SnPb solder on Ni/Ti thin films and Ni foils. J. Appl. Phys. 86, 6746 (1999).CrossRefGoogle Scholar
8Ho, C.E., Chen, Y.M. and Kao, C.R.: Reaction kinetics of solder-balls with pads in BGA packages during reflow soldering. J. Electron. Mater. 28, 1231 (1999).CrossRefGoogle Scholar
9Zeng, K. and Tu, K.N.: Six cases of reliability study of Pb-free solder joints in electronic packaging technology. Mater. Sci. Eng. Rep. R 38, 55 (2002).CrossRefGoogle Scholar
10Liu, A.A., Kim, H.K., Tu, K.N. and Totta, P.A.: Spalling of Cu6Sn5 spheroids in the solder reaction of eutectic SnPb on Cr/Cu/Au thin films. J. Appl. Phys. 80, 2774 (1996).CrossRefGoogle Scholar
11Liu, C.Y. and Wang, S.J.: Prevention of spalling by the self-formed reaction barrier layer on controlled collapse chip connections under bump metallization. J. Electron. Mater. 32, 1303 (2003).CrossRefGoogle Scholar
12Liu, C.Y. and Wang, S.J.: Study of interaction between Sn-Cu and Sn-Ni interfacial reaction by using a Cu/Sn3.5Ag/Ni sandwich structure. J. Electron. Mater. 32, 1303 (2003).Google Scholar
13Zhang, F., Li, M., Chum, C.C. and Tung, C-H.: Effects of substrate metallizations on solder/underbump metallization interfacial reactions in flip-chip packages during thermal aging. J. Mater. Res. 18, 1333 (2003).CrossRefGoogle Scholar
14Cheng, S.C. and Lin, K.L.: Interfacial evolution between Cu and Pb-free Sn–Zn–Ag–Al solders upon aging at 150 °C. J. Mater. Res. 18, 1795 (2003).CrossRefGoogle Scholar
15Jang, J.W., Kim, P.G., Tu, K.N., Frear, D. and Thompson, P.: Solder reaction-assisted crystallization of electroless Ni (P) under-bump metallization in low cost flip chip technology. J. Appl. Phys. 85, 8456 (1999).CrossRefGoogle Scholar
16Kim, P.G. and Tu, K.N.: Morphology of wetting reaction of eutectic SnPb solder on Au foils. J. Appl. Phys. 80, 3822 (1996).CrossRefGoogle Scholar
17Porter, D.A. and Easterling, K.E.: Phase Transformations in Metals and Alloys, 2nd ed. (Chapman and Hall, London, U.K., 1992), pp. 77–80Google Scholar
18Chen, 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
19Ho, C.E., Lin, Y.L. and Kao, C.R.: Strong effect of Cu concentration on the reaction between lead-free microelectronic solders and Ni. Chem. Mater. 14, 949 (2002).CrossRefGoogle Scholar
20Chen, S.W., Wu, S.H. and Lee, S.W.: Interfacial reactions in the Sn-(Cu)/Ni, Sn-(Ni)/Cu, and Sn/(Cu, Ni) systems. J. Electron. Mater. 32, 1188 (2003).CrossRefGoogle Scholar
21Alam, M.O., Chan, Y.C. and Tu, K.N.: Effect of 0.5 wt% Cu in Sn-3.5%Ag solder on the interfacial reaction with Au/Ni metallization. Chem. Mater. 15, 4340 (2003).CrossRefGoogle Scholar
22Korhonen, T.M., Su, P., Hong, S.J., Korhonen, M.A. and Li, C.Y.: Reaction of lead-free solders with CuNi metallization. J. Electron. Mater. 29, 1194 (2000).CrossRefGoogle Scholar
23Ho, C.E., Shiau, L.C. and Kao, C.R.: Inhibiting the formation of (Au1–xNix)Sn4 and reducing the consumption of Ni metallization in solder joints. J. Electron. Mater. 31, 1264 (2002).CrossRefGoogle Scholar
24Zeng, K. and Kivilahti, J.Thermodynamic calculation of saturation solubilities of some metals in Pb-free solders. Internal Report (Helsinki University of Technology, Helsinki, Finland, 2000.)Google Scholar
25 D. Suraski and K. Seelig: Controlling copper build up in automatic soldering equipment using lead-free solder, http://www.aimsolder.com.au/lead_free.htm.Google Scholar
26Lin, C.H., Chen, S.W. and Wang, C.H.: Phase equilibria and solidification properties of Sn-Cu-Ni alloys. J. Electron. Mater. 31, 907 (2002).CrossRefGoogle Scholar