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Brittle-to-ductile transition in ultrathin Ta/Cu film systems

Published online by Cambridge University Press:  31 January 2011

Patric A. Gruber ,
Eduard Arzt  and
Ralph Spolenak
Patric A. Gruber*
Affiliation:
Universität Stuttgart, Institute of Physical Metallurgy, D-70569 Stuttgart, Germany
Eduard Arzt
Affiliation:
INM Leibniz Institute for New Materials, D-66123 Saarbrücken, Germany
Ralph Spolenak*
Affiliation:
Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
*
a) Present address: Universität Karlsruhe, Institut für Zuverlässigkeit von Bauteilen und Systemen, D-76131 Karlsruhe, Germany.
b) Address all correspondence to this author. e-mail: ralph.spolenak@mat.ethz.ch
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Abstract

Current semiconductor technology demands the use of compliant substrates for flexible integrated circuits. However, the maximum total strain of such devices is often limited by the extensibility of the metallic components. Although cracking in thin films is extensively studied theoretically, little experimental work has been carried out thus far. Here, we present a systematic study of the cracking behavior of 34- to 506-nm-thick Cu films on polyamide with 3.5-to 19-nm-thick Ta interlayers. The film systems have been investigated by a synchrotron-based tensile testing technique and in situ tensile tests in a scanning electron microscope. By relating the energy release during cracking obtained from the stress-strain curves to the crack area, the fracture toughness of the Cu films can be obtained. It increases with Cu film thickness and decreases with increasing Ta film thickness. Films thinner than 70 nm exhibit brittle fracture, indicating an increasing inherent brittleness of the Cu films.

Keywords

CuFractureThin film
Type
Articles
Information
Journal of Materials Research , Volume 24 , Issue 6 , June 2009 , pp. 1906 - 1918
Copyright
Copyright © Materials Research Society 2009

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References

1Chen, Y.Au, J.Kazlas, P.Ritenour, A.Gates, H. and McCreary, M.: Flexible active-matrix electronic ink display. Nature 423, 136 (2003).CrossRefGoogle ScholarPubMed
2Gelinck, G.H., Edzer, H.Huitema, A.Veenendaal, E.V., E. van Cantatore, Schrijnemakers, L.Putten, J. van der, Geuns, T.C.T., Beenhakkers, M.Giesbers, J.B., Hiusman, B.H., Meijer, E.J., Benito, E.M., Touwslager, F.J., Marsman, A.W., van Rens, B.J.E., and Leeuw, D.M. De: Flexible active-matrix displays and shift registers based on solution-processed organic transistors. Nat. Mater. 3, 106 (2004).CrossRefGoogle ScholarPubMed
3Post, E.R., Orth, M.Russo, P.R., and Gershenfeld, N.: E-broidery: Design and fabrication of textile-based computing. IBM Syst. J. 39, 840 (2000).CrossRefGoogle Scholar
4Bonderover, E. and Wagner, S.: A woven inverter circuit for e-textile applications. IEEE Electron Device Lett. 25, 295 (2004).CrossRefGoogle Scholar
5Wagner, S.Lacour, S.P., Jones, J.Hsu, P.H.I., Sturm, J.C., Li, T. and Suo, Z.G.: Electronic skin: Architecture and components. Physica E 25, 326 (2004).CrossRefGoogle Scholar
6Meyer, J.U.: Retina implant—A bioMEMS challenge. Sens. Actuators, A 97-98, 1 (2002).CrossRefGoogle Scholar
7Stett, A.Egert, U.Guenther, E.Hofmann, F.Meyer, T.Nisch, W. and Haemmerle, H.: Biological application of microelectrode arrays in drug discovery and basic research. Anal. Bioanal. Chem. 377, 486 (2003).CrossRefGoogle ScholarPubMed
8Zhang, S.Sun, D.Fu, Y.Q., and Du, H.J.: Toughness measurement of thin films: A critical review. Surf. Coat. Technol. 198, 74 (2005).CrossRefGoogle Scholar
9Handge, U.A., Leterrier, Y.Rochat, G.Sokolov, I.M., and Blumen, A.: Two scaling domains in multiple cracking phenomena. Phys. Rev. E: Stat. Phys., Plasmas, Fluids, Relat. Interdiscip. Topics 62, 7807 (2000).CrossRefGoogle ScholarPubMed
10Rochat, G.Leterrier, Y.Fayet, P. and Manson, J.A.E.: Mechanical analysis of ultrathin oxide coatings on polymer substrates in situ in a scanning electron microscope. Thin Solid Films 437, 204 (2003).CrossRefGoogle Scholar
11Xiang, Y.Li, T.Suo, Z.G., and Vlassak, J.J.: High ductility of a metal film adherent on a polymer substrate. Appl. Phys. Lett. 87, 61910 (2005).CrossRefGoogle Scholar
12Heinrich, M.Gruber, P.Orso, S.Handge, U.A., and Spolenak, R.: Dimensional control of brittle nanoplatelets. A statistical analysis of a thin film cracking approach. Nano Lett. 6, 2026 (2006).Google ScholarPubMed
13Handge, U.A.: Analysis of a shear-lag model with nonlinear elastic stress transfer for sequential cracking of polymer coatings. J. Mater. Sci. 37, 4775 (2002).CrossRefGoogle Scholar
14Leterrier, Y.Boogh, L.Andersons, J. and Manson, J.A.: Adhesion of silicon oxide layers on poly(ethylene terephthalate). I. Effect of substrate properties on coating's fragmentation process. J. Polym. Sci., Part B: Polym. Phys. 35, 1449 (1997).3.0.CO;2-6>CrossRefGoogle Scholar
15Leterrier, Y.Andersons, J.Pitton, Y. and Manson, J.A.: Adhesion of silicon oxide layers on poly(ethylene terephthalate). II. Effect of coating thickness on adhesive and cohesive strengths. J. Polym. Sci., Part B: Polym. Phys. 35, 1463 (1997).3.0.CO;2-4>CrossRefGoogle Scholar
16Jansson, N.E., Leterrier, Y. and Manson, J.A.E.: Modeling of multiple cracking and decohesion of a thin film on a polymer substrate. Eng. Fract. Mech. 73, 2614 (2006).CrossRefGoogle Scholar
17Jansson, N.E., Leterrier, Y.Medico, L. and Manson, J.A.E.: Calculation of adhesive and cohesive fracture toughness of a thin brittle coating on a polymer substrate. Thin Solid Films 515, 2097 (2006).CrossRefGoogle Scholar
18Alaca, B.E., Selby, J.C., Saif, M.T.A., and Sehitoglu, H.: Biaxial testing of nanoscale films on compliant substrates: Fatigue and fracture. Rev. Sci. Instrum. 73, 2963 (2002).CrossRefGoogle Scholar
19Chen, Z. and Gan, Z.H.: Fracture toughness measurement of thin films on compliant substrate using controlled buckling test. Thin Solid Films 515, 3305 (2007).CrossRefGoogle Scholar
20Böhm, J., Gruber, P.Spolenak, R.Stierle, A.Wanner, A., and Arzt, E.: Tensile testing of ultrathin polycrystalline films: A synchrotronbased technique. Rev. Sci. Instrum. 75, 1110 (2004).CrossRefGoogle Scholar
21Gruber, P.Böhm, J., Wanner, A.Sauter, L.Spolenak, R. and Arzt, E.: Size effect on crack formation in Cu/Ta and Ta/Cu/Ta thin film systems, in Nanoscale Materials and Modeling—Relations Among Processing, Mircostructure and Mechanical Properties, edited by Anderson, P.M., Foecke, T.Misra, A. and Rudd, R.E. (Mater. Res. Soc. Symp. Proc. 821, Warrendale, PA, 2004), P2.7.Google Scholar
22Gruber, P.Böhm, J., Onuseit, F.Wanner, A.Spolenak, R. and Arzt, E.: Size effects on yield strength and strain hardening for ultra thin Cu films with and without passivation: A study by synchrotron and bulge test techniques. Acta Mater. 56, 2318 (2008).CrossRefGoogle Scholar
23BeuthJr, J.L..: Cracking of thin bonded films in residual tension. Int. J. Solids Struct. 29, 1657 (1992).CrossRefGoogle Scholar
24Xia, Z.C. and Hutchinson, J.W.: Crack patterns in thin films. J. Mech. Phys. Solids 48, 1107 (2000).CrossRefGoogle Scholar
25Beuth, J.L. and Klingbeil, N.W.: Cracking of thin films bonded to elastic-plastic substrates. J. Mech. Phys. Solids 44, 1411 (1996).CrossRefGoogle Scholar
26Vlassak, J.J.: Channel cracking in thin films on substrates of finite thickness. Int. J. Fract. 119, 299 (2003).CrossRefGoogle Scholar
27Begley, M.R. and Bart-Smith, H.: The electro-mechanical response of highly compliant substrates and thin stiff films with periodic cracks. Int. J. Solids Struct. 42, 5259 (2005).CrossRefGoogle Scholar
28Begley, M.R., Bart-Smith, H., Scott, O.N., Jones, M.H., and Reed, M.L.: The electro-mechanical response of elastomer membranes coated with ultra-thin metal electrodes. J. Mech. Phys. Solids 53, 2557 (2005).CrossRefGoogle Scholar
29Li, T.Huang, Z.Y., Suo, Z.Lacour, S.P., and Wagner, S.: Stretchability of thin metal films on elastomer substrates. Appl. Phys. Lett. 85, 3435 (2004).CrossRefGoogle Scholar
30Li, T.Huang, Z.Y., Xi, Z.C., Lacour, S.P., Wagner, S. and Suo, Z.: Delocalizing strain in a thin metal film on a polymer substrate. Mech. Mater. 37, 261 (2005).CrossRefGoogle Scholar
31Li, T. and Suo, Z.: Deformability of thin metal films on elastomer substrates. Int. J. Solids Struct. 43, 2351 (2006).CrossRefGoogle Scholar
32Dundurs, J. and Bogy, D.B.: Edge-bonded dissimilar orthogonal elastic wedges under normal and shear loading. J. Appl. Mech. 36, 650 (1969).CrossRefGoogle Scholar
33Hertzberg, R.W.: Deformation and Fracture Mechanics of Engineering Materials (John Wiley & Sons, NY, 1989), pp. 289–294.Google Scholar
34Hsia, K.J., Suo, Z. and Yang, W.: Cleavage due to dislocation confinement in layered materials. J. Mech. Phys. Solids 42, 877 (1994).CrossRefGoogle Scholar
35Moody, N.R., Medlin, D.Boehme, D. and Norwood, D.P.: Film thickness effects on the fracture of tantalum nitride on aluminum nitride thin film systems. Eng. Fract. Mech. 61, 107 (1998).CrossRefGoogle Scholar
36Wellner, P.Kraft, O.Dehm, G.Andersons, J. and Arzt, E.: Channel cracking of b-NiAl thin films on Si substrates. Acta Mater. 52, 2325 (2004).CrossRefGoogle Scholar