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Effect of Zn on the intermetallics formation and reliability of Sn-3.5Ag solder on a Cu pad

Published online by Cambridge University Press:  31 January 2011

Y.K. Jee ,
Y.H. Ko  and
Jin Yu
Y.K. Jee*
Affiliation:
Department of Material Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 305-701, Korea
Y.H. Ko
Affiliation:
Department of Material Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 305-701, Korea
Jin Yu
Affiliation:
Department of Material Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Yuseong-gu, Daejeon 305-701, Korea
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

Varying amounts of Zn (1, 3, and 7 wt%) were added to Sn–3.5Ag solder on a Cu pad, and the resultant solder joint microstructures after a reflow and isothermal aging (150 °C, up to 500 h) were investigated using scanning electron microscopy, energy dispersive x-ray, and x-ray diffraction, which were subsequently correlated to the results of microhardness and drop tests. Zinc was effective in improving the drop resistance of Sn–3.5Ag solder on the Cu pad, and an addition of 3 wt% Zn nearly doubled the number of drops-to-failure (Nf). The beneficial role of Zn was ascribed to suppression of Cu6Sn5 and precipitation of Zn-containing intermetallic compounds (IMCs). However, the Zn effect was reduced as Cu6Sn5 and Ag3Sn precipitated in a joint IMC layer after prolonged aging. The interface between Ag5Zn8 and Cu5Zn8 was resistant to drop impact, but two other layered IMC structures of Cu6Sn5/Cu3Sn and Cu5Zn8/Cu6Sn5 were not.

Keywords

Chemical reactionDiffusionFracture
Type
Articles
Information
Journal of Materials Research , Volume 22 , Issue 7 , July 2007 , pp. 1879 - 1887
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1Muller, J., Griese, H., Zuber, K.H., Reichl, H. Schischke, K.: Environmental aspects of microelectronics. Adv. Electron. Packag. 3, 1575 2001Google Scholar
2Li, M., Zhang, F., Chen, W.T., Zeng, K., Tu, K.N., Balkan, H. Elenius, P.: Intefacial microstructure evolution between eutectic SnAgCu solder and Al/Ni(V)/Cu thin films. J. Mater. Res. 17, 1612 2002CrossRefGoogle Scholar
3Kang, S.K., Rai, R.S. Purushothaman, S.: Interfacial reactions during soldering with lead-tin eutectic and lead (Pb)-free, tin-rich solder. J. Electron. Mater. 25, 1113 1996CrossRefGoogle Scholar
4Chou, C.Y. Chen, S.W.: Phase equlibria of the Sn–Zn–Cu ternary system. Acta Mater. 5, 2393 2006CrossRefGoogle Scholar
5McCormack, M., Kammlott, G.W., Chen, H.S. Jin, S.: New lead-free, Sn–Ag–Zn–Cu solder alloy with improved mechanical properties. Appl. Phys. Lett. 65, 1233 1994CrossRefGoogle Scholar
6Wu, C.M.L. Law, C.M.T.: Microstructure evolution and shear strength of eutectic Sn–9Zn and Sn–0.7Cu lead-free BGA solder balls. Proc. HDP 04, 47 2004Google Scholar
7Mavoori, H., Chin, J., Vaynman, S., Moran, B., Keer, L. Fine, M.E.: Creep, stress relaxation, and plastic deformation in Sn–Ag and Sn–Zn eutectic solders. J. Electron. Mater. 41, 1269 1997Google Scholar
8Kang, S.K., Shih, D.Y., Leonard, D., Henderson, D.W., Gosselin, T., Cho, S., Yu, J. Choi, W.K.: Controlling Ag3Sn plate formation in near-ternary-eutectic Sn–Ag–Cu solder by minor Zn alloying. J. Metals 56, 34 2004Google Scholar
9Suganuma, K., Murata, T., Noguchi, H. Toyoda, Y.: Heat resistance of Sn-9Zn solder/Cu interface with or without coating. J. Mater. Res. 15, 884 2000CrossRefGoogle Scholar
10Yanagawa, H., Imamura, T., Ide, E., Hirose, A. Kobayashi, K.: Investigation of the interfacial reaction between Sn-Zn-Bi lead-free solder and Cu electrode. J. Jpn. Inst. Electron. Packag. 7, 47 2004CrossRefGoogle Scholar
11Chonan, Y., Komiyama, T., Onuki, J., Urao, R., Kimura, T. Nagano, T.: Influence of P content in electroless plated Ni–P alloy film on interfacial structures and strength between Sn–Zn solder and plated Au/Ni–P alloy film. Mater. Trans. 43, 1887 2002CrossRefGoogle Scholar
12Chang, T.C., Wang, M.C. Hon, M.S.: Growth and morphology of the intermetallic compounds formed at the Sn–9Zn–2.5Ag/Cu interface. J. Alloys Compd. 402, 141 2005CrossRefGoogle Scholar
13Yang, S.C., Ho, C.E., Chang, C.W. Kao, C.R.: Strong Zn concentration effect on the soldering reactions between Sn-based solders and Cu. J. Mater. Res. 21, 2436 2006CrossRefGoogle Scholar
14 JESD22-B111, Board Level Drop Test Method of Components for Handheld Electronic Components (JEDEC Solid State Technology Association, 2003Google Scholar
15Chen, W.T., Tsai, R.Y., Lin, Y.L. Kao, C.R.: Effect of concentration on the reactions between Sn–Ag–Cu solders and Ni. J. Electron. Mater. 31, 584 2002Google Scholar
16Alam, M.O., Chen, Y.C. Tu, K.N.: Effect of reaction time and P content on mechanical strength of the interface formed between eutectic Sn–Ag solder and Au/electroless Ni(P)/Cu bond pad. J. Appl. Phys. 94, 4108 2003CrossRefGoogle Scholar
17Sohn, Y.C., Jin, Yu., Kang, S.K., Shih, D.Y. Lee, T.Y.: Spalling of intermetallic compounds during the reaction between lead-free solders and electroless Ni–P metallization. J. Mater. Res. 19(8), 2428 2004CrossRefGoogle Scholar
18Sohn, Y.C. Yu, J.: Correlation between chemical reaction and brittle fracture found in electroless Ni(P)/immersion gold-solder interconnection. J. Mater. Res. 20, 1931 2005CrossRefGoogle Scholar
19Ho, C.E., Tsai, R.Y., Lin, Y.L. Kao, C.R.: Effect of Cu concentration on the reactions between Sn–Ag–Cu solder and Ni. J. Electron. Mater. 31, 392 2002CrossRefGoogle Scholar
20Chiu, T.C., Zeng, K., Strierman, R., Edwards, D. Ano, K.: Effect of thermal aging on board level drop reliability for Pb-free BGA packages, in Proc. 54th Electronic Component and Technology Conference, 2004 1256Google Scholar
21Yu, J., Sohn, Y.C., Kim, J.Y., Jee, Y.K. Ko, Y.H.: Impact reliabilities of lead-free solder joints with Ni(P), Cu and Ni metallizations, in Proc. International Conference on Electronics Packaging, 2006 271Google Scholar
22Choi, W.K.: Interfacial phenomena and characterization of Sn-Ag-based solder alloy systems for electronic packaging. Ph.D. thesis, Korea Advanced Institute of Science and Technology 2001Google Scholar
23Jeong, S.W., Kim, J.H. Lee, H.M.: Effect of cooling rate on growth of the intermetallic compound and fracture mode of near eutectic Sn–Ag–Cu/Cu pad: Before and after aging. J. Electron. Mater. 33, 1530 2004CrossRefGoogle Scholar
24Mei, Z., Ahmad, M., Hu, M. Ramakrishna, G.: Kirkendall voids at Cu/solder interface and their effects on solder joint reliability, in Proc 55th Electronic Component and Technology Conference, 2005 415Google Scholar
25Zeng, K., Stierman, R., Chiu, T.C. Edwards, D.: Kirkendall void formation in eutectic SnPb solder joints on bare Cu and its effect on joint reliability. J. Appl. Phys. 97, 024508 2005CrossRefGoogle Scholar
26Kang, S.K., Leonard, D., Shih, D.Y., Gignac, L., Henderson, D.W., Cho, S.I. Yu, J.: Interfacial reactions of Sn–Ag–Cu solder modified by minor Zn alloying addition. J. Electron. Mater. 35, 479 2006CrossRefGoogle Scholar
27Yu, C.H. Lin, K.L.: Early stage soldering reaction and interfacial microstructure formed between molten Sn–Zn–Ag solder and Cu substrate. J. Mater. Res. 20, 1242 2005CrossRefGoogle Scholar
28Song, J.M., Liu, P.C., Shih, C.L. Lin, K.L.: Role of Ag in the formation of interfacial intermetallic phases in Sn–Zn soldering. J. Electron. Mater. 34, 1249 2005CrossRefGoogle Scholar
29Date, M., Tu, K.N., Shoji, T., Fujiyoshi, M. Sato, K.: Interfacial reactions and impact reliability of Sn–Zn solder joints on Cu or electroless Au/Ni(P) bond-pads. J. Mater. Res. 19, 2887 2004CrossRefGoogle Scholar
30Yu, S.P., Wang, M.C. Hon, M.H.: Formation of intermetallic compounds at eutectic Sn–Zn-Al solder/Cu interface. J. Mater. Res. 16, 76 2001CrossRefGoogle Scholar
31Jang, J.W., Silva A, D., Lin, J.K. Frear, D.: Mechanical tensile fracture behaviors of solid-state-annealed eutectic SnPb and lead-free solder flip chip bumps, in Proc 53th Electronic Component and Technology Conference, 2003 680Google Scholar
32Chong, D.Y.R., Che, F.X., Xu, L.H., Toh, H.J., Pang, J.H.L., Xiong, B.S. Lim, B.K.: Performance assessment on board-level drop reliability for chip scale packages (Fine-pitch BGA), in Proc 56th Electronic Component and Technology Conference, 2006 356Google Scholar
33Kim, J.Y., Sohn, Y.C. Yu, J.: Effect of Cu content on the mechanical reliability of Ni/Sn–3.5Ag system. J. Mater. Res. 22, 770 2007CrossRefGoogle Scholar
34Kang, S.K., Lauro, P.A., Shih, D.Y., Henderson, D.W. Puttlitz, K.J.: Microstructure and mechanical properties of lead-free solders and solder joints used in microelectronic applications. IBM J. Res. & Dev. 49(4), 607 2005CrossRefGoogle Scholar