Hostname: page-component-848d4c4894-r5zm4 Total loading time: 0 Render date: 2024-06-15T05:56:43.620Z Has data issue: false hasContentIssue false
  • English
  • Français

Measuring the elastic modulus and residual stress of freestanding thin films using nanoindentation techniques

Published online by Cambridge University Press:  31 January 2011

Erik G. Herbert ,
Warren C. Oliver ,
Maarten P. de Boer  and
George M. Pharr
Erik G. Herbert*
Affiliation:
University of Tennessee, College of Engineering, Department of Materials Science and Engineering, Knoxville, Tennessee 37996-2200
Warren C. Oliver
Affiliation:
Agilent Technologies, Nanotechnology Measurements Division, Research and Development, Oak Ridge, Tennessee 37830
Maarten P. de Boer
Affiliation:
MEMS Technology Department, Sandia National Labs, Albuquerque, New Mexico 87185-1084
George M. Pharr
Affiliation:
University of Tennessee, College of Engineering, Department of Materials Science and Engineering, Knoxville, Tennessee 37996-2200; and Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6132
*
a) Address all correspondence to this author. e-mail: eherbert@utk.edu or erikgherbert@gmail.com
Get access

Abstract

A new method is proposed to determine the elastic modulus and residual stress of freestanding thin films based on nanoindentation techniques. The experimentally measured stiffness-displacement response is applied to a simple membrane model that assumes the film deformation is dominated by stretching as opposed to bending. Dimensional analysis is used to identify appropriate limitations of the proposed model. Experimental verification of the method is demonstrated for Al/0.5 wt% Cu films nominally 22 µm wide, 0.55 µm thick, and 150, 300, and 500 µm long. The estimated modulus for the four freestanding films match the value measured by electrostatic techniques to within 2%, and the residual stress to within 19.1%. The difference in residual stress can be completely accounted for by thermal expansion and a modest change in temperature of 3 °C. Numerous experimental pitfalls are identified and discussed. Collectively, these data and the technique used to generate them should help future investigators make more accurate and precise measurements of the mechanical properties of freestanding thin films using nanoindentation.

Keywords

Elastic propertiesMicroelectromechanical systems (MEMS)Thin film
Type
Articles
Information
Journal of Materials Research , Volume 24 , Issue 9 , September 2009 , pp. 2974 - 2985
Copyright
Copyright © Materials Research Society 2009

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

1Spearing, S.M.: Materials issues in microelectromechanical systems (MEMS). Acta Mater. 48(1), 179 (2000).CrossRefGoogle Scholar
2Nix, W.D.: Mechanical-properties of thin films. Metall. Trans. A 20(11), 2217 (1989).CrossRefGoogle Scholar
3Huang, H.B. and Spaepen, F.: Tensile testing of free-standing Cu, Ag and Al thin films and Ag/Cu multilayers. Acta Mater. 48(12), 3261 (2000).CrossRefGoogle Scholar
4Senturia, S.D.: Microsystem Design (Kluwer Publishers, Boston, 2001).CrossRefGoogle Scholar
5Haque, M.A. and Saif, M.T.A.: Mechanical behavior of 30–50 nm thick aluminum films under uniaxial tension. Scr. Mater. 47(12), 863 (2002).CrossRefGoogle Scholar
6Heinen, D., Bohn, H.G. and Schilling, W.: On the mechanical strength of freestanding and substrate-bonded Al thin-films. J. Appl. Phys. 77(8), 3742 (1995).CrossRefGoogle Scholar
7Read, D.T.: Young's modulus of thin films by speckle interferometry. Meas. Sci. Technol. 9(4), 676 (1998).CrossRefGoogle Scholar
8Oliver, W.C. and Pharr, G.M.: Measurement of hardness and elastic modulus by instrumented indentation: Advances in understanding and refinements to methodology. J. Mater. Res. 19(1), 3 (2004).CrossRefGoogle Scholar
9Hay, J.L. and Pharr, G.M.: Instrumented indentation testing, in ASM Handbook, vol. 8, edited by Kuhn, H. and Medlun, D. (ASM International, Materials Park, OH, 2000), p. 232.Google Scholar
10Herbert, E.G., Oliver, W.C. and Pharr, G.M.: On the measurement of yield strength by spherical indentation. Philos. Mag. 86(33–35), 5521 (2006).CrossRefGoogle Scholar
11Taljat, B. and Pharr, G.M.: Measurement of residual stress by load and depth sensing spherical indentation, in Thin Films—Stresses and Mechanical Properties VIII, edited by Vinci, R., Kraft, O., Moody, N., Besser, P., and Shaffer, E., II (Mater. Res. Soc. Symp. Proc. 594, Warrendale, PA, 2000), p. 519.Google Scholar
12Pharr, G.M., Harding, D.S. and Oliver, W.C.: Measurement of fracture toughness in thin films and small volumes using nanoindentation methods, in Mechanical Properties and Deformation Behavior of Materials Having Ultra-Fine Microstructures, edited by Nastasi, M., Parkin, D., and Gleiter, H. (Nato ASI Series E: App. Sci. 233, Kluwer Publishers, Boston, 1993), p. 449.Google Scholar
13Lucas, B.N. and Oliver, W.C.: Indentation power-law creep of high-purity indium. Metall. Mater. Trans. A 30(3), 601 (1999).CrossRefGoogle Scholar
14Northen, M.T. and Turner, K.L.: Meso-scale adhesion testing of integrated micro- and nano-scale structures. Sens. Actuators, A130, 583 (2006).CrossRefGoogle Scholar
15VanLandingham, M.R.: Review of instrumented indentation. J. Res. Nat. Inst. Stand. Technol. 108(4), 249 (2003).CrossRefGoogle ScholarPubMed
16Oyen, M.L. and Cook, R.F.: Load-displacement behavior during sharp indentation of viscous-elastic-plastic materials. J. Mater. Res. 18(1), 139 (2003).CrossRefGoogle Scholar
17Tweedie, C.A. and Vliet, K.J. Van: Contact creep compliance of viscoelastic materials via nanoindentation. J. Mater. Res. 21(6), 1576 (2006).CrossRefGoogle Scholar
18Herbert, E.G., Oliver, W.C. and Pharr, G.M.: Nanoindentation and the dynamic characterization of viscoelastic solids. J. Phys. D: Appl. Phys. 41(7), 074021 (2008).CrossRefGoogle Scholar
19Kraft, O. and Volkert, C.A.: Mechanical testing of thin films and small structures. Adv. Eng. Mater. 3(3), 99 (2001).3.0.CO;2-2>CrossRefGoogle Scholar
20Emery, R.D. and Povirk, G.L.: Tensile behavior of free-standing gold films. Part I. Coarse-grained films. Acta Mater. 51(7), 2067 (2003).Google Scholar
21Emery, R.D. and Povirk, G.L.: Tensile behavior of free-standing gold films. Part II. Fine-grained films. Acta Mater. 51(7), 2079 (2003).Google Scholar
22Read, D.T. and Dally, J.W.: A new method for measuring the strength and ductility of thin-films. J. Mater. Res. 8(7), 1542 (1993).CrossRefGoogle Scholar
23Lee, D., Wei, X., Chen, X., Zhao, M., Jun, S.C., Hone, J., Herbert, E.G., Oliver, W.C. and Kysar, J.W.: Microfabrication and mechanical properties of nanoporous gold at the nanoscale. Scr. Mater. 56(5), 437 (2007).CrossRefGoogle Scholar
24Wang, L. and Prorok, B.C.: Investigation of the influence of grain size, texture and orientation on the mechanical behavior of freestanding polycrystalline gold films, in Mechanics of Nano-scale Materials and Devices, edited by Misra, A., Sullivan, J.P., Huang, H., Lu, K., and Asif, S. (Mater. Res. Soc. Symp. Proc. 924E, Warrendale, PA, 2006), 0924–Z03.Google Scholar
25Boer, M.P. de, DelRio, F.W. and Baker, M.S.: On-chip test structure suite for free-standing metal film mechanical property testing, Part I—Analysis. Acta Mater. 56(14), 3344 (2008).CrossRefGoogle Scholar
26Boer, M.P. de, Corwin, A.D., Kotula, P.G., Baker, M.S., Michael, J.R., Subhash, G. and Shaw, M.J.: On-chip test structure suite for free-standing metal film mechanical property testing, Part II—Experiments. Acta Mater. 56(14), 3313 (2008).CrossRefGoogle Scholar
27Zhang, T.Y., Su, Y.J., Qian, C.F., Zhao, M.H. and Chen, L.Q.: Microbridge testing of silicon nitride thin films deposited on silicon wafers. Acta Mater. 48(11), 2843 (2000).CrossRefGoogle Scholar
28Espinosa, H.D., Prorok, B.C. and Fischer, M.: A methodology for determining mechanical properties of freestanding thin films and MEMS materials. J. Mech. Phys. Solids 51(1), 47 (2003).CrossRefGoogle Scholar
29Huh, Y.H., Kim, D., Hahn, J.H., Kim, G.S., Kee, C.D., Yeon, S.C. and Kim, Y.H.: Observation of micro-tensile behavior of thin film TiN and Au using ESPI technique, in Thin Films—Stresses and Mechanical Properties XI, edited by Buchheit, T.E., Minor, A.M., Spolenak, R., and Takashima, K. (Mater. Res. Soc. Symp. Proc. 875, Warrendale, PA, 2005), O4.15.Google Scholar
30Sinclair, M.B., Boer, M.P. de and Corwin, A.D.: Long-working-distance incoherent-light interference microscope. Appl. Opt. 44 (36), 7714 (2005).CrossRefGoogle ScholarPubMed
31Wang, L. and Prorok, B.C.: Characterization of the strain rate dependent behavior of nanocrystalline gold films. J. Mater. Res. 23(1), 55 (2008).CrossRefGoogle Scholar