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Evolution of microstructure and stress of and associated whisker growth on Sn layers sputter-deposited on Cu substrates

Published online by Cambridge University Press:  31 January 2011

M. Sobiech
Affiliation:
Max Planck Institute for Metals Research, D-70569 Stuttgart, Germany; and Robert Bosch GmbH, D-72770 Reutlingen, Germany
C. Krüger
Affiliation:
Institute for Materials Science, University of Stuttgart, D-70569 Stuttgart, Germany
U. Welzel*
Affiliation:
Max Planck Institute for Metals Research, D-70569 Stuttgart, Germany
J.Y. Wang
Affiliation:
Max Planck Institute for Metals Research, D-70569 Stuttgart, Germany
E.J. Mittemeijer
Affiliation:
Max Planck Institute for Metals Research, D-70569 Stuttgart, Germany; and Institute for Materials Science, University of Stuttgart, D-70569 Stuttgart, Germany
W. Hügel
Affiliation:
Robert Bosch GmbH, D-72770 Reutlingen, Germany
*
a)Address all correspondence to this author. e-mail: u.welzel@mf.mpg.de
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Abstract

After sputter deposition of Sn (layer thickness of 350 nm) on Cu substrates and during subsequent aging at room temperature, Cu and Sn reacted to form the intermetallic phase Cu6Sn5 in the Sn layer at the Cu/Sn interface, which led within a few hours of aging to the development of a compressive stress parallel to the Cu/Sn interface in the Sn layer. One day after aging at room-temperature whisker formation occurred on the surface of the Sn layer. It was shown that whisker growth is associated with long-range Sn diffusion parallel to the Cu/Sn interface. Sn layers of the same thickness sputter deposited on pure Si substrates exhibited throughout the same aging time at room temperature a tensile stress parallel to the Cu/Sn interface (no intermetallic phase formation took place) and whisker formation did not occur. The interrelationship of intermetallic compound formation, stress development, and whisker growth is discussed.

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Articles
Copyright
Copyright © Materials Research Society 2010

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References

REFERENCES

1.Arnold, S.M.: Repressing the growth of tin whiskers. Plating 53, 96 (1966)Google Scholar
2.Directive 2002/95/EC of the European Parliament and of the Council of 27 January 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment Off. J. Eur. Union L37, 19 (2003)Google Scholar
3.Compton, K.G., Mendizza, A., Arnold, S.M.: Filamentary growth on metal surfaces—Whiskers. Corrosion 7, 327 (1951)CrossRefGoogle Scholar
4.Key, P.L.: Surface morphology of whisker crystals of tin, zinc and cadmium, Proc. of the 20th Electronic Components Conference (IEEE 1970)155Google Scholar
5.Galyon, G.T.: Annotated tin whisker bibliography and anthology. IEEE Trans. Electron. Packag. Manuf. 28, 94 (2005)CrossRefGoogle Scholar
6.Ellis, W.C., Gibbons, D.F., Treuting, R.C.: Growth of metal whiskers from the solid, Growth and Perfection of Crystals edited by R.H. Doremus, B.W. Roberts, and D. Turnbull (Wiley, New York 1958)102120Google Scholar
7.Glazunova, V.K., Kudryavtsev, N.T.: An investigation of the conditions of spontaneous growth of filiform crystals on electrolytic coatings. Zh. Prikl. Khim. 36, 543 (1963)Google Scholar
8.Furuta, N., Hamamura, K.: Growth mechanism of proper tin whisker. Jpn. J. Appl. Phys. 9, 1404 (1969)CrossRefGoogle Scholar
9.Fisher, R.M., Darken, L.S., Carroll, K.G.: Accelerated growth of tin whiskers. Acta Metall. 2, 368 (1954)CrossRefGoogle Scholar
10.Herring, C., Galt, J.K.: Elastic and plastic properties of very small metal specimens. Phys. Rev. 85, 1060 (1952)CrossRefGoogle Scholar
11.LeBret, J.B., Norton, M.G.: Electron microscopy study of tin whisker growth. J. Mater. Res. 18, 585 (2003)CrossRefGoogle Scholar
12.Koonce, S.E., Arnold, S.M.: Growth of metal whiskers. J. Appl. Phys. 24, 365 (1953)CrossRefGoogle Scholar
13.Eshelby, J.D.: A tentative theory of metallic whisker growth. Phys. Rev. 91, 755 (1953)CrossRefGoogle Scholar
14.Frank, F.C.: On tin whiskers. Philos. Mag. 44, 854 (1953)CrossRefGoogle Scholar
15.Hasiguti, R.R.: A tentative explanation of the accelerated growth of tin whiskers. Acta Metall. 3, 200 (1955)CrossRefGoogle Scholar
16.Franks, J.: Growth of whiskers in the solid phase. Acta Metall. 6, 103 (1958)CrossRefGoogle Scholar
17.Lindborg, U.: A model for the spontaneous growth of zinc, cadmium and tin whiskers. Acta Metall. 24, 181 (1976)CrossRefGoogle Scholar
18.Tu, K.N.: Irreversible processes of spontaneous whisker growth in bimetallic Cu–Sn thin-film reactions. Phys. Rev. B 49, 2030 (1994)CrossRefGoogle ScholarPubMed
19.Lee, B.Z., Lee, D.N.: Spontaneous growth mechanism of tin whiskers. Acta Mater. 46, 3701 (1998)CrossRefGoogle Scholar
20.Tu, K.N., Chen, C., Wu, A.T.: Stress analysis of spontaneous Sn whisker growth. J. Mater. Sci.- Mater. Electron. 18, 269 (2007)CrossRefGoogle Scholar
21.Boettinger, W.J., Johnson, C.E., Bendersky, L.A., Moon, K-W., Williams, M.E., Stafford, G.R.: Whisker and hillock formation on Sn, Sn–Cu and Sn–Pb electrodeposits. Acta Mater. 53, 5033 (2005)CrossRefGoogle Scholar
22.Smetana, J.: Theory of tin whisker growth: The end game. IEEE Trans. Electron. Packag. Manuf. 30, 11 (2007)CrossRefGoogle Scholar
23.Kakeshita, T., Shimizu, K., Kawanaka, R., Hasegawa, T.: Grain size effect of electro-plated tin coating on whisker growth. J. Mater. Sci. 17, 2560 (1982)CrossRefGoogle Scholar
24.Boguslavsky, I., Bush, P.: Recrystallization principles applied to whisker growth in tin, Proc. of the APEX Conference (Anaheim, CA 2003)S12Google Scholar
25.Osenbach, J.W.: Creep and its effect on Sn whisker growth. J. Appl. Phys. 106, 094903 (2009)CrossRefGoogle Scholar
26.Hutchinson, B., Oliver, J., Nylen, M., Hagström, J.: Whisker growth from tin coatings. Mater. Sci. Forum 467–470, 465 (2004)CrossRefGoogle Scholar
27.Buchovecky, E.J., Du, N., Bower, A.F.: A model of Sn whisker growth by coupled plastic flow and grain-boundary diffusion. Appl. Phys. Lett. 94, 191904 (2009)CrossRefGoogle Scholar
28.Buchovecky, E.J., Jadhav, N., Bower, A.F., Chason, E.: Finite element modeling of stress evolution in Sn films due to growth of the Cu6Sn5 intermetallic compound. J. Electron. Mater. 38, 2676 (2009)CrossRefGoogle Scholar
29.Tu, K.N.: Interdiffusion and reaction in bimetallic Cu–Sn thin films. Acta Metall. 21, 347 (1973)CrossRefGoogle Scholar
30.Dyson, B.F., Anthony, T.R., Turnbull, D.: Interstitial diffusion of copper in tin. J. Appl. Phys. 38, 3408 (1967)CrossRefGoogle Scholar
31.Kumar, K.S., Reinbold, L., Bower, A.F., Chason, E.: Plastic deformation processes in Cu/Sn bimetallic films. J. Mater. Res. 23, 2916 (2008)CrossRefGoogle Scholar
32.Reinbold, L., Jadhav, N., Chason, E., Kumar, K.S.: Relation of Sn whisker formation to intermetallic growth: Results from a novel Sn–Cu “bimetal ledge specimen”. J. Mater. Res. 24, 3583 (2009)CrossRefGoogle Scholar
33.Chason, E., Jadhav, N., Chan, W.L., Reinbold, L., Kumar, K.S.: Whisker formation in Sn and Pb–Sn coatings: Role of intermetallic growth, stress evolution, and plastic deformation processes. Appl. Phys. Lett. 92, 171901 (2008)CrossRefGoogle Scholar
34.Sobiech, M., Welzel, U., Schuster, R., Mittemeijer, E.J., Hügel, W., Seekamp, A., Müller, V.: The microstructure and state of stress of Sn thin films after post-plating annealing: An explanation for the suppression of whisker formation?, Proc. of the 57th Electronic Components and Technology Conference (Reno, NV 2007)192Google Scholar
35.Choi, W.J., Lee, T.Y., Tu, K.N., Tamura, N., Celestre, S., MacDowell, A.A., Bong, Y.Y., Nguyen, L.: Tin whiskers studied by synchrotron radiation scanning x-ray micro-diffraction. Acta Mater. 51, 6253 (2003)CrossRefGoogle Scholar
36.Sobiech, M., Welzel, U., Mittemeijer, E.J., Hügel, W., Seekamp, A.: Driving force for Sn whisker growth in the system Cu–Sn. Appl. Phys. Lett. 93, 011906 (2008)CrossRefGoogle Scholar
37.Sobiech, M., Wohlschlögel, M., Welzel, U., Mittemeijer, E.J., Hügel, W., Seekamp, A., Liu, W., Ice, G.E.: Local, submicron strain gradients as the cause of Sn whisker growth. Appl. Phys. Lett. 94, 221901 (2009)CrossRefGoogle Scholar
38.Pinsky, D.A.: The role of dissolved hydrogen and other trace impurities on propensity of tin deposits to grow whiskers. Microelectron. Reliab. 48, 675 (2008)CrossRefGoogle Scholar
39.Leoni, M., Welzel, U., Scardi, P.: Polycapillary optics for materials science studies: Instrumental effects and their correction. J. Res. Nat. Inst. Stand. Technol. 109, 27 (2004)CrossRefGoogle ScholarPubMed
40.Welzel, U., Ligot, J., Lamparter, P., Vermeulen, A.C., Mittemeijer, E.J.: Stress analysis of polycrystalline thin films and surface regions by x-ray diffraction. J. Appl. Crystallogr. 38, 1 (2005)CrossRefGoogle Scholar
41.Welzel, U., Mittemeijer, E.J.: Diffraction stress analysis of macroscopically elastically anisotropic specimens: On the concepts of diffraction elastic constants and stress factors. J. Appl. Phys. 93, 9001 (2003)CrossRefGoogle Scholar
42.Gale, W.F.: Smithells Metals Reference Book (Butterworths, London 2004)Google Scholar
43.Ghosh, G., Asta, M.: Phase stability, phase transformations, and elastic properties of Cu6Sn5: Ab initio calculations and experimental results. J. Mater. Res. 20, (11)3102 (2005)CrossRefGoogle Scholar
44.Zhang, W., Egli, A., Schwager, F., Brown, N.: Investigation of Sn–Cu intermetallic compounds by AFM: New aspects of the role of intermetallic compounds in whisker formation. IEEE Trans. Electron. Packag. Manuf. 28, 85 (2005)CrossRefGoogle Scholar
45.Woodrow, T.A.: Tracer diffusion in whisker-prone tin platings, Proc. of the SMTA International Conference (Rosemont, IL 2006)1Google Scholar
46.Touloukian, Y.S., Kirby, R.K., Taylor, R.K., Desai, P.D.: Thermal Expansion—Metallic Elements and Alloys (Plenum, New York 1975)Google Scholar
47.Floro, J.A., Chason, E., Cammarata, R.C., Srolovitz, D.J.: Physical origins of intrinsic stresses in Volmer–Weber thin films. MRS Bull. 27, 19 (2002)CrossRefGoogle Scholar
48.Tello, J.S., Bower, A.F., Chason, E., Sheldon, B.W.: Kinetic model of stress evolution during coalescence and growth of polycrystalline thin films. Phys. Rev. Lett. 98, 216104 (2007)CrossRefGoogle ScholarPubMed
49.Taylor, L.: Metals Handbook Vol. 2 (ASM International, Materials Park OH 1990)Google Scholar
50.Arzt, E.: Size effects in materials due to microstructural and dimensional constraints: A comparative review. Acta Mater. 46, 5611 (1998)CrossRefGoogle Scholar
51.Sobiech, M., Wohlschlögel, M., Welzel, U., Mittemeijer, E.J., Hügel, W., Seekamp, A., Garza, M., Koyuncu, M., Liu, W., Ice, G.E.: Driving force for whisker formation on Sn thin films deposited on Cu, 3rd International Symposium on Tin Whiskers in Denmark (CALCE, Copenhagen 2009)Google Scholar
52.Kawanaka, R., Fujiwara, K., Nango, S., Hasegawa, T.: Influence of impurities on the growth of tin whiskers. Jpn. J. Appl. Phys. 22, 917 (1983)CrossRefGoogle Scholar
53.Xu, C., Fan, C., Vysotskaya, A., Abys, J., Zhang, Y., Hopkins, L., Stevie, F.: Understanding whisker phenomenon—Part II, competitive mechanisms, Proc. of the AESF SUR/FIN Conference (Nashville, TN 2001)Google Scholar