Abstract
The wetting behavior of SnAg based Pb-free solders on Cu and Cu substrates plated with Au, Pd, and Au/Pd thin films have been studied. The wetting angle and kinetics of interfacial reaction were measured. The Au-plated substrates exhibit better wetting than the Pd-plated substrates. In the case of SnAg on Pd-plated Cu, SEM observation revealed that the solder cap was surrounded by an innerring of Cu−Sn compound and an outer ring of Pd−Sn compound. This implies that the molten SnAg solder had removed the Pd and wetted the Cu directly in the equilibrium state. The effects of pre-doping Cu in the SnAg solder on wetting behavior were also investigated. We found that wettability decreases with increasing Cu content in the solder. We also observed that the SnAgCu solders have a lower Cu consumption rate than the SnAg solder.
Similar content being viewed by others
References
C.Y. Liu and K.N. Tu, J. Mater. Res. 13, 37 (1998).
S. Choi, T.R. Bieler, J.P. Lucas, and K.N. Subramanian, J. Electron. Mater. 28, 1209 (1999).
D.R. Flanders, E.G. Jacobs, and R.F. Pinizzotto, J. Electron. Mater. 26, 883 (1997).
S.K. Kang, R.S. Rai, and S. Purushothaman, J. Electron. Mater. 25, 1113 (1996).
I. Artaki, A.M. Jackson, and P.T. Vianco, J. Electron. Mater. 23, 757 (1994).
R.D. Denmand, Soldering to Au Coating, ITRI publication No. 736 (ITRI, 1996).
Y. Wang, H.K. Kim, H.K. Liou, and K.N. Tu, Scripta Metall. 32, 2087 (1995).
Y. Wang and K.N. Tu, Appl. Phys. Lett. 67, 1069 (1995).
R.J. Klein-Wassink, Soldering in Electronics (Ayr, Scotland: Electrochemical Publications, 1984).
J.H. Westbrook, editor, Intermetallic Compounds (New York: John Wiley & Sons Ltd., 1967).
H.A.H. Steen, The Effect of Impurities on the Microstructure and Solidification Behavior of Eutectic Sn−Pb Solders, Report No. IM-1643 (Swedish Institute for Metals Research, 1982).
B.S. Berry and I. Ames, IBM J. Res. Dev. 13, 286 (1969).
P.A. Totta and R.P. Sopher, IBM J. Res. Dev. 13, 226 (1969).
H.K. Kim and K.N. Tu, Appl. Phys. Lett. 68, 2004 (1996).
T. Young, Philos. Trans R. Soc. London 95, 65 (1805).
C.Y. Liu and K.N. Tu, Phys. Rev. E 58, 6308 (1998).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Liu, C.Y., Li, J., Vandentop, G.J. et al. Wetting reaction of Sn-Ag based solder systems on Cu substrates plated with Au and/or Pd layer. J. Electron. Mater. 30, 521–525 (2001). https://doi.org/10.1007/s11664-001-0092-1
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s11664-001-0092-1