The most frequent failure of wireless, handheld, and movable consumer electronic products is an accidental drop to the ground. The impact may cause interfacial fracture of wire-bonds or solder joints between a Si chip and its packaging module. Existing metrologies, such as ball shear, and pull test cannot well represent the shock reliability of the package. In this study, a micro-impact machine is utilized to test the impact reliability of three kinds of lead-free solders: 99Sn1Ag, 98.5Sn1Ag0.5Cu and 97.5Sn1Ag0.5Cu1In (hereafter called Sn1Ag, Sn1Ag0.5Cu, and Sn1Ag0.5Cu1In). The effect of thermal aging on the impact toughness is also evaluated in this study. We find a ductile-to-brittle transition in SnAg (Cu) solder joints after thermal aging. The impact toughness is enhanced by the thermal aging. This is a combination effect of the growth of intermetallic compound (IMC) at the interface provided strong bonding, and the softening of the solder bulk during the thermal aging absorbed more energy during plastic deformation.
This is a preview of subscription content, access via your institution.
We’re sorry, something doesn't seem to be working properly.
Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.
Kinuko Mishiro, et al, “Effect of the drop impact on BGA/CSP package reliability,” Microelectronics Reliability, 42 (2002), pp. 77–82.
Nishiura M, Nakayama A, Sakatani S, Kohara Y, Uenishi K, Kobayashi KF., “Mechanical strength and microstructure of BGA joints using lead-free solders,” Mater Trans., 43 (2002), pp.1802.
Tz-Cheng Chiu, Kejun Zeng, Roger Stierman and Darvin Edwards, Kazuaki Ano, “Effect of Thermal Aging on Board Level Drop Reliability for Pb-free BGA Packages,” The proceedings of the 54th ECTC, Las Vegas, NV, 2004, pp.1256.
Shoji T, Yamamoto K, Kajiwara R, Morita T, Sato K, Date M., Proceedings of the 16th JIEP Annual Meeting, 2002, pp.97.
M. Date, T. Shoji, M. Fujiyoshi, K. Sato, and K. N. Tu, “Ductile-to-brittle transition in Sn-Zn solder joints measured by impact test,” Scripta Materialia, 51 (2004), pp.641.
John M. Holt, editor, “Charpy Impact Test: Factors and Variables” ASTM STP 1072, Philadelphia, PA, (1990).
K. Zeng and K. N. Tu, “Six cases of reliability study of Pb-free solder joints in electronic packaging technology,” Mater. Sci. Eng., R., 38 (2002), pp. 55.
M. O. Alam, Y. C. Chan, and K. N. Tu, “Effect of 0.5 wt. % Cu addition in the Sn-3.5%Ag solder on the interfacial reaction with Au/Ni metallization,” Chemistry of Materials, 15 (2003), pp.4340-4342.
About this article
Cite this article
Ou, S., Xu, Y., Tu, K.N. et al. A Study of Impact Reliability of Lead-free BGA Balls on Au/Electrolytic Ni/Cu Bond Pad. MRS Online Proceedings Library 863, B10.5 (2004). https://doi.org/10.1557/PROC-863-B10.5