Investigation of Intermetallic Phases Formed in Lead-Free Solders

Abstract:

Industry should gradually replace the tin-lead solder alloys used traditionally in the soft soldering technology by lead-free soldering alloys, which raises a lot of new technological and scientific problems to be solved. The introduction and application of lead-free alloys caused a number of soldering defects not observed earlier; mechanisms of their formation are still unclear. One of such defects is whisker formation, another one is intensified formation of intermetallic phases. The appearance of undesired intermetallic phases in the soldering material spoils its mechanical properties; therefore it is particularly important that these phases do not form in electronic components. Besides, the formation of intermetallic compounds may occur in the soldering bath, thus making the soldering process difficult or even impossible.Tin-copper-nickel and tin-silver-copper alloys are suitable for the replacement of tin-lead alloys. The components of these alloys were studied. After metallographic examination of the specimens the occurrence of intermetallic phases was determined by the XRD method. The identification of intermetallic phases was carried out by using literature data and phase diagrams.

• Periodical: Materials Science Forum (Volume 812)
• Pages: 357-362
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.812.357
• Online since: February 2015
• Authors: Erzsebet Nagy, Anett Gyenes, Alíz Molnár, Zoltán Gácsi
• Keywords: IMC, Lead-Free Solder, X-Ray Diffraction

References

[1] ASM Handbook, Volume 3: Alloy phase diagrams, ASM International, (1992).

[2] Kattner, U.R.: Phase diagrams for Lead-free solder alloys, Journal of The Minerals, Metals & Materials Society, 54, 2002, pp.45-51.

DOI: 10.1007/bf02709189

[3] Nogita, K.: Stabilisation of Cu6Sn5 by Ni in Sn-0. 7Cu-0, 05Ni lead-free solder alloys, Intermetallics, 18, 2010, pp.145-149.

DOI: 10.1016/j.intermet.2009.07.005

[4] Nogita, K.; Nishimura, T.: Nickel stabilized hexagonal (Cu, Ni)6Sn5 in Sn-Cu-Ni lead-free solder alloys, Scripta Materialia, 59, 2008, pp.191-194.

DOI: 10.1016/j.scriptamat.2008.03.002

[5] Gourlay, C.M.; Nogita, K.; Read, J.; Dahle, A.K.: Intermetallic formation and fluidity in Sn-rich Sn-Cu-Ni alloys, Journal of Electronic Materials, 39, 1, 2010, pp.56-69.

DOI: 10.1007/s11664-009-0962-5

[6] Snugovsky, L.; Snugovsky, P.; Perovic, D.D.; Rutter, J.W.: Phase equilibria in Sn rich corner of Cu-Ni-Sn system, Materials Science and Technology, 22, 8, 2006, pp.899-902.

DOI: 10.1179/174328406x109249

[7] Ventura, T.; Terzi, S.; Rappaz, M.; Dahle, A.K.: Effects of Ni addition, trace elements and solidification kinetics on microstructure formation in Sn-0. 7Cu solder, Acta Materialia, 59, 2011, pp.4197-4206.

DOI: 10.1016/j.actamat.2011.03.044

[8] http: /www. metallurgy. nist. gov/phase/solder/agcusn. html.

[9] D.A. Shnawah, M.F.M. Sabri and I. A. Badruddin, A review on thermal cycling and drop impact reliability of SAC solder joint in portable electronic products, Microelectronics Reliability 52, 2012, p.90.

DOI: 10.1016/j.microrel.2011.07.093

[10] K. Nogita, D. Mu, S. D Mcdonald, J. Read, Y.Q. Wu: Effect of Ni on phase stability and thermal expansion of Cu6-xNixSn5 (X=0, 0. 5, 1, 1. 5 and 2), Intermetallics 26, 2012, pp.78-85.

DOI: 10.1016/j.intermet.2012.03.047