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Impact of printed wiring board coatings on the reliability of lead-free chip-scale package interconnections

Published online by Cambridge University Press:  01 November 2004

T.T. Mattila ,
V. Vuorinen  and
J.K. Kivilahti
T.T. Mattila
Affiliation:
Laboratory of Electronics Production Technology, Helsinki University of Technology, 02150 Espoo, Finland
V. Vuorinen
Affiliation:
Laboratory of Electronics Production Technology, Helsinki University of Technology, 02150 Espoo, Finland
J.K. Kivilahti
Affiliation:
Laboratory of Electronics Production Technology, Helsinki University of Technology, 02150 Espoo, Finland
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Abstract

When lead-free solder alloys mix with lead-free component and board metallizations during reflow soldering, the solder interconnections become multicomponent alloy systems whose microstructures cannot be predicted on the basis of the SnPb metallurgy. To better understand the influences of these microstructures on the reliability of lead-free electronics assemblies, SnAgCu-bumped components were reflow-soldered with near-eutectic SnAgCu solder pastes on Ni(P)|m.Au- and organic solderability preservative (OSP)-coated printed wiring boards and tested under cyclic thermal shock loading conditions. The reliability performance under thermomechanical loading was found to be controlled by the kinetics of recrystallization. Because ductile fracturing of the as-soldered tin-rich colonies would require a great amount of plastic work, the formation of continuous network of grain boundaries by recrystallization is needed for cracks to nucleate and propagate intergranularly through the solder interconnections. Detailed microstructural observations revealed that cracks nucleate and grow along the grain boundaries especially between the recrystallized part and the non-recrystallized part of the interconnections. The thermal cycling test data were analyzed statistically by combining the Weibull statistics and the analysis of variance. The interconnections on Ni(P)|m.Au were found out to be more reliable than those on Cu|m.OSP. This is due to the extensive dissolution of Cu conductor, in the case of the Cu|m.OSP assemblies, into molten solder that makes the microstructure to differ noticeably from that of the Ni(P)|m.Au interconnections. Because of large primary Cu6Sn5 particles, the Cu-enriched interconnections enhance the onset of recrystallization, and cracking of the interconnections is therefore faster. The solder paste composition had no statistically significant effect on the reliability performance.

Keywords

FatigueMicrostructureShock loading

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Type
Articles
Information
Journal of Materials Research , Volume 19 , Issue 11 , November 2004 , pp. 3214 - 3223
Copyright
Copyright © Materials Research Society 2004

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References

REFERENCES

1Kivilahti, J.K. and Kulojärvi, K. in Design and Reliability of Solders and Solder Interconnections, edited by Mahidhara, R.K. (TMS, Warrendale, PA, 1997), pp. 377–384.Google Scholar
2Puligandla, V., Dunford, S. and Kivilahti, J.K. in Handbook of Lead(Pb)-Free Technology for Microelectronics Assemblies, edited by Puttliz, K. and Stalter, K. (Marcel Dekker Inc., New York, 2004), p. 1026Google Scholar
3Sohn, J.E.: Are lead-free solder joints reliable? Circuits Assembly June, 32(2002).Google Scholar
4Syed, A.: Reliability and Au Embrittlement of Lead Free Solders for BGA Applications. 2001 International Symposium on Advanced Packaging Materials, pp. 143–147.Google Scholar
5Amagai, M.: Characterization of chip scale packaging materials. Microelectronics Reliability 39, 1365 (1999).Google Scholar
6Wang, Z.P., Tan, Y.M. and Chua, K.M.: Board level reliability assessment of chip scale packages. Microelectronics Reliability 39, 1351 (1999).CrossRefGoogle Scholar
7Lee, S.R., Lui, B.H.W., Kong, Y.H., Baylon, B., Leung, T., Umali, P. and Agtarap, H.: Assessment of board level solder joint reliability for PBGA assemblies with lead-free solder joints. Soldering and Surface Mount 14, 46 (2002).Google Scholar
8Bradley, E. and Banerji, K.: Effect of PCB Finish on the Reliability and Wettability of Ball Grid Array Packages. IEEE Transactions on Components, Packaging and Manufacturing Technology 19, 320 (1996).Google Scholar
9Hirano, T., Fukuda, K., Ito, K., Kiga, T. and Taniguchi, Y.: Reliability of Lead Free Solder Joint by Using Chip Size Package. Electronics and the Environment. Proceedings of the 2001 IEEE International Symposium, Piscataway, NJ, pp. 285–289.Google Scholar
10Vianco, P.T.: An overview of surface finishes and their role in printed circuit board solderability and solder joint performance. Soldering and Surface Mount 25, 6 (1998).Google Scholar
11Kulojärvi, K. and Kivilahti, J.K.: Effect of Dissolution and intermetallic formation on the reliability of flip chip joints—comparison between Cu and Ni. Microelectronics International 15, 20 (1998).Google Scholar
12Kang, S.K., Shih, D.Y., Fogel, K., Lauro, P., Yim, M.J., Advocate, G., Griffin, M., Goldsmith, C., Henderson, D.W., Gosselin, T., King, D., Konrad, J., Sarkhel, A. and Puttliz, K.J.: Interfacial Reactio Studies on Lead (PB)-Free Solder Alloys. Electronic Components and Technology Conference 2001. Institute of Electrical and Electronics Engineers, Piscataway, NJ.Google Scholar
13Sigelko, J., Choi, S., Subramanian, K.N. and Lucas, J.P.: The effect of small additions of copper on the aging kinetics of the intermetallic layer and intermetallic particles of eutectic tin-silver solder joints. Journal of Electric Materials 29, 1307 (2000).CrossRefGoogle Scholar
14Ho, C.E., Tsai, R.Y., Lin, Y.L. and Kao, C.R.: Effect of Cu concentration on the reactions between Sn-Ag-Cu solders and Ni. Journal of Electronic Materials 31, 584 (2002).Google Scholar
15Bader, W.G.: Dissolution and Formation on Intermetallics in the Soldering Process. Proceedings of the Conference on Physical Metallurgy and Metal Joining, edited by Kossowsky, R. and Glicksman, M.F. (TMS/AIME, Warrendale, PA, 1980).Google Scholar
16Bader, W.G.: Dissolution of Au, Ag, Pd, Pt, Cu and Ni in a molten Sn-lead solder. Welding Journal 48, 551 (1969).Google Scholar
17Chada, S., Fournelle, R.A., Laub, W. and Shangguan, D.: Copper substrate dissolution in eutectic Sn-Ag solder and its effect on microstructure. J. Electron. Mater. 29, 1214 (2000).CrossRefGoogle Scholar
18 “IPMA”-- The Thermodynamic Databank for Interconnection and Packaging Materials. Helsinki University of Technology, Helsinki (2001).Google Scholar
19O’Connor, P.: Practical Reliability Engineering, 3rd ed. (John Wiley & Sons Ltd., West Sussex, 1991) p. 431.Google Scholar
20Zeng, K., Vuorinen, V. and Kivilahti, J.K.: Intermetallic Reactions between Lead-free SnAgCu Solder and Ni(P)/Au Finish on PWB. Proceedings of the 51st Electronic Components and Technology Conference, edited by John Lau. (Institute of Electrical and Electronics Engineers, Piscataway, NJ, 2001) pp. 693–698.Google Scholar
21Oberndorff, P.: Ph.D. Thesis. Eindhoven University of Technology, The Netherlands (2001).Google Scholar
22Peng, W., Zeng, K. and Kivilahti, J.K.: Potential Pb-free Solder Systems. Report Series TKK-EVT-1. (Helsinki Univeristy of Technology, Helsinki, 2000).Google Scholar
23Leslie, W.C., Michalak, T.J. and Aul, F.W. in Iron and Its Dilute Solid Solutions, edited by Spencer, C.W. and Werner, F.E. (Interscience Puhlishers, New York, 1963).Google Scholar
24Cahn, R.W.: Physical Metallurgy (NH Physics, Amsterdam, 1965).Google Scholar
25Koivisto, J.: M.S. Thesis. Helsinki University of Technology (2004).Google Scholar