Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-17T19:11:21.122Z Has data issue: false hasContentIssue false
  • English
  • Français

Effects of Be and Co addition on the growth of Sn whiskers and the properties of Sn-based Pb-free solders

Published online by Cambridge University Press:  12 June 2012

Jaewon Chang ,
Sun-Kyoung Seo ,
Moon Gi Cho ,
Dong Nyung Lee ,
Kyoo-Sik Kang  and
Hyuck Mo Lee
Jaewon Chang
Affiliation:
Department of Materials Science and Engineering, KAIST, Daejeon 305-701, Republic of Korea
Sun-Kyoung Seo
Affiliation:
Department of Materials Science and Engineering, KAIST, Daejeon 305-701, Republic of Korea; andPackage Development Team, Semiconductor R&D Center, Samsung Electronics, Hwasung-city, Gyeonggi-do 445-701, Republic of Korea
Moon Gi Cho
Affiliation:
Department of Materials Science and Engineering, KAIST, Daejeon 305-701, Republic of Korea; andPackage Development Team, Semiconductor R&D Center, Samsung Electronics, Hwasung-city, Gyeonggi-do 445-701, Republic of Korea
Dong Nyung Lee
Affiliation:
Department of Materials Science and Engineering, Seoul National University, Gwanak-gu, Seoul 151-742, Republic of Korea; and R&D Center, Iljin Materials Co., Ltd., Mapo-gu, Seoul 121-716, Republic of Korea
Kyoo-Sik Kang
Affiliation:
R&D Center, Iljin Materials Co., Ltd., Mapo-gu, Seoul 121-716, Republic of Korea
Hyuck Mo Lee*
Affiliation:
Department of Materials Science and Engineering, KAIST, Daejeon 305-701, Republic of Korea
*
a)Address all correspondence to this author. e-mail: [email protected]
Get access

Abstract

To enhance the reliability of Pb-free solders in high temperature and high humidity conditions, the minor alloying elements of Be and Co are investigated in terms of the growth of Sn whiskers and various properties of Sn-based Pb-free solders. Sn whisker growth is suppressed by adding up to 0.02 wt% Be to Sn-based solders. Adding Be and Co can effectively reduce the undercooling of Sn–1.0Ag–0.5Cu (wt%) solders. And the microstructures of Sn–1.0Ag–0.5Cu–0.02Be solders are similar to those of Sn–1.0Ag–0.5Cu. Furthermore, adding Co to solders increases the microhardness number as a result of the solid solution hardening. Adding Be causes no changes in the morphology or thickness of Cu6Sn5 at the Cu/OSP (organic solderability preservative) under bump metallurgy interface. However, the scallop-like Cu6Sn5 microstructure changes to a flat (Cu,Co)6Sn5 microstructure when 0.05 wt% of Co is added to Sn–1.0Ag–0.5Cu–0.02Be solders.

Keywords

solderingBeCo
Type
Articles
Information
Journal of Materials Research , Volume 27 , Issue 14 , 28 July 2012 , pp. 1877 - 1886
Copyright
Copyright © Materials Research Society 2012

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

1.Zaal, J.J.M., van Driel, W.D., Kessels, F.J.H.G., and Zhang, G.Q.: Correlating drop impact simulations with drop impact testing using high-speed camera measurements. J. Electron. Packag. 131(1), 0110071 (2009).CrossRefGoogle Scholar
2.Long, X., Dutta, I., Sarihan, V., and Frear, D.R.: Deformation behavior of Sn-3.8Ag-0.7Cu solder at intermediate strain rates: Effect of microstructure and test conditions. J. Electron. Mater. 37(2), 189 (2008).CrossRefGoogle Scholar
3.European Union: Directive 2002/95/EC of the European parliament and of the council of 27 January 2003 on WEEE. Off. J. Eur. Union L37/24 (2003).Google Scholar
4.Moon, K-W., Boettinger, W.J., Kattner, U.R., Biancaniello, F.S., and Handwerker, C.A.: Experimental and thermodynamic assessment of Sn-Ag-Cu solder alloys. J. Electron. Mater. 29(10), 1122 (2000).CrossRefGoogle Scholar
5.Seo, S-K., Kang, S.K., Cho, M.G., Shih, D-Y., and Lee, H.M.: The crystal orientation of β-Sn grains in Sn-Ag and Sn-Cu solders affected by their interfacial reactions with Cu and Ni(P) under bump metallurgy. J. Electron. Mater. 38(12), 2461 (2009).CrossRefGoogle Scholar
6.Huh, S-H., Kim, K-S., and Suganuma, K.: Effect of Ag addition on the microstructural and mechanical properties of Sn-Cu eutectic solder. Mater. Trans. 42(5), 739 (2001).CrossRefGoogle Scholar
7.Schetty, R.: Minimization of tin whisker formation for lead-free electronics finishing. Circuit World 27(2), 17 (2001).CrossRefGoogle Scholar
8.Chuang, T-H.: Rapid whisker growth on the surface of Sn-3Ag-0.5Cu-1.0Ce solder joints. Scr. Mater. 55(11), 983 (2006).CrossRefGoogle Scholar
9.Ye, H., Xue, S., Zhang, L., Xiao, Z., Hu, Y., Lai, Z., and Zhu, H.: Sn whisker growth in Sn-9Zn-0.5Ga-0.7Pr lead-free solder. J. Alloys Compd. 509(5), L52 (2011).CrossRefGoogle Scholar
10.Su, P., Howell, J., and Chopin, S.: A statistical study of Sn whisker population and growth during elevated temperature and humidity tests. IEEE Trans. Electron. Packag. Manuf. 29(4), 246 (2006).CrossRefGoogle Scholar
11.Lee, B-Z. and Lee, D.N.: Spontaneous growth mechanism of tin whiskers. Acta Mater. 46(10), 3701 (1998).CrossRefGoogle Scholar
12.Barsoum, M.W., Hoffman, E.N., Doherty, R.D., Gupta, S., and Zavaliangos, A.: Driving force and mechanism for spontaneous metal whisker formation. Phys. Rev. Lett. 93(20), 206104 (2004).CrossRefGoogle ScholarPubMed
13.Tu, K.N. and Li, J.C.M.: Spontaneous whisker growth on lead-free solder finishes. Mater. Sci. Eng., A 406(1–2), 131 (2005).CrossRefGoogle Scholar
14.Galyon, G.T. and Palmer, L.: An integrated theory of whisker formation: The physical metallurgy of whisker formation and the role of internal stresses. IEEE Trans. Electron. Packag. Manuf. 28(1), 17 (2005).CrossRefGoogle Scholar
15.Tu, K.N.: Interdiffusion and reaction in bimetallic Cu-Sn thin films. Acta Mater. 21(4), 347 (1973).CrossRefGoogle Scholar
16.Jeong, S.W., Kim, J.H., and 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(12), 1530 (2004).CrossRefGoogle Scholar
17.Cho, M.G., Kang, S.K., Shih, D-Y., and Lee, H.M.: Effects of minor additions of Zn on interfacial reactions of Sn-Ag-Cu and Sn-Cu solders with various Cu substrates during thermal aging. J. Electron. Mater. 36(11), 1501 (2006).CrossRefGoogle Scholar
18.Sohn, Y.C., Yu, J., Kang, S.K., Shih, D-Y., and 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 (2004).CrossRefGoogle Scholar
19.Kim, D.H., Cho, M.G., Seo, S-K., and Lee, H.M.: Effects of Co addition on bulk properties of Sn-3.5Ag solder and interfacial reactions with Ni-P UBM. J. Electron. Mater. 38(1), 39 (2009).CrossRefGoogle Scholar
20.Kim, K.S., Huh, S.H., and Suganuma, K.: Effects of fourth alloying additive on microstructures and tensile properties of Sn-Ag-Cu alloy and joints with Cu. Microelectron. Reliab. 43(2), 259 (2002).CrossRefGoogle Scholar
21.de Sousa, I., Henderson, D.W., Parry, L., Kang, S.K., and Shih, D-Y.: The influence of low level doping on the thermal evolution of SAC alloy solder joints with Cu pad structures. In Proceedings of the Fifty Sixth Electronic Components Technology Conference (IEEE, Piscataway, NJ, 2006). pp. 1454–1462.Google Scholar
22.Vo, N., Kwoka, M., and Bush, P.: Tin whisker test standardization. IEEE Trans. Electron. Packag. Manuf. 28(1), 3 (2005).CrossRefGoogle Scholar
23.Okamoto, H. and Tanner, L., eds.: Phase Diagrams of Binary Beryllium Alloys (ASM International, Metal Park, OH, 1987).Google Scholar
24.Subramanian, P.R., Charkrabarti, D.J., and Laughlin, D.E., eds.: Phase Diagrams of Binary Copper Alloys (ASM International, Metal Park, OH, 1994).Google Scholar
25.Cho, M.G., Kim, H.Y., Seo, S-K., and Lee, H.M.: Enhancement of heterogeneous nucleation of β-Sn phases in Sn-rich solders by adding minor alloying elements with hexagonal closed packed structures. Appl. Phys. Lett. 95(2), 021905 (2009).CrossRefGoogle Scholar
26.Cheng, F., Nishikawa, H., and Takemoto, T.: Microstructural and mechanical properties of Sn-Ag-Cu lead-free solders with minor addition of Ni and/or Co. J. Mater. Sci. 43(10), 3643 (2008).CrossRefGoogle Scholar
27.Dudek, M.A., Sidhu, R.S., Chawla, N., and Renavikar, M.: Microstructure and mechanical behavior of novel rare earth-containing Pb-free solders. J. Electron. Mater. 35(12), 2088 (2006).CrossRefGoogle Scholar
28.Dudek, M.A. and Chawla, N.: The effect of rare earth (La, Ce, and Y) additions on the microstructure and mechanical behavior of Sn-3.9Ag-0.7Cu solder alloy. Metall. Mater. Trans. A 41, 610 (2010).CrossRefGoogle Scholar
29.Xiao, Q., Nguyen, L., and Armstrong, W.D.: The anomalous microstructural, tensile, and aging response of thin-cast Sn3.9Ag0.67Cu lead-free solder. J. Electron. Mater. 34(5), 617 (2005).CrossRefGoogle Scholar
30.Gao, F. and Takemoto, T.: Effects of addition participation in the interfacial reaction on the growth patterns of Cu6Sn5-based IMCs during reflow process. J. Alloys Compd. 421(1–2), 283 (2006).CrossRefGoogle Scholar
31.Cho, M.G., Kang, S.K., Seo, S.K., Shih, D-Y., and Lee, H.M.: Interfacial reaction and microstructures of Sn-0.7Cu-xZn solders with Ni-P UBM during thermal aging. J. Electron. Mater. 38(11), 2242 (2009).CrossRefGoogle Scholar
32.Nishikawa, H., Komatsu, A., and Takemoto, T.: Interfacial reaction between Sn-Ag-Co solder and metals. Mater. Trans. 46(11), 2394 (2005).CrossRefGoogle Scholar
33.Song, J-M., Liu, Y-R., Su, C-W., Lai, Y-S., and Chiu, Y-T.: Intermetallic formation induced substrate dissolution in electroless Ni(P)-solder interconnections. J. Mater. Res. 23(9), 2545 (2008).CrossRefGoogle Scholar