A critical review of microscale mechanical testing methods used in the design of microelectromechanical systems

Microelectromechanical systems (MEMS) technologies are evolving at a rapid rate with increasing activity in the design, fabrication, and commercialization of a wide variety of microscale systems and devices. The importance of accurate mechanical property measurement for successful design was realized early on in the development of this field. Consequently, there exist many different techniques to measure quantities such as the Young's modulus (E), yield strength (σY), fracture strength (σF), residual stress (σF), and residual stress gradient (∇σR) of microscale structures and materials. We review and critically compare several of the important techniques including the microtension test, axisymmetric plate bend test, microbeam bend test, M-test, wafer curvature measurements, dynamic (resonant) tests, fabrication of passive strain sensors, and Raman spectroscopy. We discuss the characteristics of typical test structures, and the common sources of structure-related errors in measurement. A rational approach for the selection of test techniques for the design of microsystems is suggested.

[1]  S. Senturia,et al.  M-TEST: A test chip for MEMS material property measurement using electrostatically actuated test structures , 1997 .

[2]  Oliver Paul,et al.  Mechanical properties of thin films from the load deflection of long clamped plates , 1998 .

[3]  K. Najafi,et al.  Bent-beam strain sensors , 1996 .

[4]  Timothy P. Weihs,et al.  Mechanical deflection of cantilever microbeams: A new technique for testing the mechanical properties of thin films , 1988 .

[5]  R. L. Edwards,et al.  A new technique for measuring the mechanical properties of thin films , 1997 .

[6]  C. J. Wilson,et al.  Fracture testing of silicon microcantilever beams , 1996 .

[7]  David Wood,et al.  Raman and finite-element analysis of a mechanically strained silicon microstructure , 2001 .

[8]  J. Schweitz,et al.  Micromechanical fracture strength of silicon , 1990 .

[9]  David Cebon,et al.  Materials Selection in Mechanical Design , 1992 .

[10]  J. Schweitz,et al.  Evaluation of mechanical materials properties by means of surface micromachined structures , 1999 .

[11]  Frans Spaepen,et al.  Tensile testing of free-standing Cu, Ag and Al thin films and Ag/Cu multilayers , 2000 .

[12]  Ingrid De Wolf,et al.  Stress measurements in Si microelectronics devices using Raman spectroscopy , 1999 .

[13]  Stephen P. Timoshenko,et al.  Vibration problems in engineering , 1928 .

[14]  D. W. Burns,et al.  Diagnostic microstructures for the measurement of intrinsic strain in thin films , 1992 .

[15]  C. Kim,et al.  Microscale material testing of single crystalline silicon: process effects on surface morphology and tensile strength , 2000 .

[16]  J. Esteve,et al.  Stress measurement by microRaman spectroscopy of polycrystalline silicon structures , 1995 .

[17]  N. C. MacDonald,et al.  MICROINSTRUMENTS FOR SUBMICRON MATERIAL STUDIES , 1998 .

[18]  J. Maibach,et al.  A new analytical solution for the load-deflection of square membranes , 1995 .

[19]  Bruce M. Clemens,et al.  THE ELASTIC BIAXIAL MODULUS OF AG-PD MULTILAYERED THIN FILMS MEASURED USING THE BULGE TEST , 1994 .

[20]  J. Schweitz,et al.  Influence of surface coatings on elasticity, residual stresses, and fracture properties of silicon microelements , 1989 .

[21]  Jean-François Manceau,et al.  Measurement of residual stresses in a plate using a vibrational technique-application to electrolytic nickel coatings , 1996 .

[22]  M. A. Haque,et al.  In-situ tensile testing of nano-scale specimens in SEM and TEM , 2002 .

[23]  Oliver Kraft,et al.  Mechanical Testing of Thin Films and Small Structures , 2001 .

[24]  S. M. Spearing,et al.  On the flexural creep of single-crystal silicon , 2000 .

[25]  S. Spearing,et al.  Controlling and Testing the Fracture Strength of Silicon on the Mesoscale , 2000 .

[26]  O. Tabata,et al.  Mechanical property measurements of thin films using load-deflection of composite rectangular membranes , 1989 .

[27]  C. Kim,et al.  Measurement of mechanical properties for MEMS materials , 1999 .

[28]  R. Howe,et al.  A micro strain gauge with mechanical amplifier , 1997 .

[29]  J. Söderkvist,et al.  High-sensitivity surface micromachined structures for internal stress and stress gradient evaluation , 1997 .

[30]  S. M. Hu,et al.  Critical stress in silicon brittle fracture, and effect of ion implantation and other surface treatments , 1982 .

[31]  Daniel Josell,et al.  A new method for tensile testing of thin films , 1993 .

[32]  F. Brotzen,et al.  Mechanical testing of thin films , 1994 .

[33]  Joost J. Vlassak,et al.  A new bulge test technique for the determination of Young’s modulus and Poisson’s ratio of thin films , 1992 .

[34]  O. Tabata,et al.  Specimen size effect on tensile strength of surface-micromachined polycrystalline silicon thin films , 1998 .

[35]  Surface micromachined ring test structures to determine mechanical properties of compressive thin films , 2001 .

[36]  R.K. Gupta,et al.  Electronically probed measurements of MEMS geometries , 2000, Journal of Microelectromechanical Systems.

[37]  Hisaaki Tobushi,et al.  Analysis of the mechanical behavior of shape memory polymer membranes by nanoindentation, bulging and point membrane deflection tests , 2000 .

[38]  M. P. Boer,et al.  Tribology of MEMS , 2001 .

[39]  R. F. Bunshah,et al.  Measurement of mechanical properties , 1971 .

[40]  R. Howe,et al.  Microfabricated structures for the in situ measurement of residual stress, Young’s modulus, and ultimate strain of thin films , 1987 .

[41]  K. Petersen,et al.  Young’s modulus measurements of thin films using micromechanics , 1979 .

[42]  V. T. Srikar,et al.  Micro-Raman measurement of bending stresses in micromachined silicon flexures , 2003 .

[43]  W. Knauss,et al.  A new microtensile tester for the study of MEMS materials with the aid of atomic force microscopy , 2002 .

[44]  C. J. Wilson,et al.  Fracture testing of bulk silicon microcantilever beams subjected to a side load , 1996 .

[45]  B. Culshaw,et al.  Measurement of the mechanical properties of silicon microresonators , 1991 .

[46]  V. T. Srikar,et al.  The reliability of microelectromechanical systems (MEMS) in shock environments , 2002 .

[47]  Alex A. Volinsky,et al.  Interfacial toughness measurements for thin films on substrates , 2002 .

[48]  Mark G. Allen,et al.  In situ measurement of mechanical properties of polyimide films using micromachined resonant string structures , 1999 .

[49]  Stuart B. Brown,et al.  Subcritical crack growth in silicon MEMS , 1999 .

[50]  E.R. Deutsch,et al.  Effect of support compliance and residual stress on the shape of doubly supported surface-micromachined beams , 2000, Journal of Microelectromechanical Systems.

[51]  M. Madou.  Fundamentals of microfabrication , 1997 .

[52]  Gannavaram D. Vishakhadatta.  Finite Element Modeling of , 1993 .

[53]  H. Baltes,et al.  Strongly buckled square micromachined membranes , 1999 .

[54]  F. J. V. Preissig.  Applicability of the classical curvature-stress relation for thin films on plate substrates , 1989 .

[55]  John C. Bravman,et al.  Stress relaxation of free-standing aluminum beams for microelectromechanical systems applications , 2000 .

[56]  David M. Follstaedt,et al.  Finite-element modeling of nanoindentation , 1999 .

[57]  Joost J. Vlassak,et al.  Mechanical Behavior of Thin Films , 1996 .

[58]  Josef Binder,et al.  Comparison of stress measurement techniques in surface micromachining , 1997 .

[59]  Subra Suresh,et al.  Large deformation and geometric instability of substrates with thin-film deposits , 1997 .

[60]  William D. Nix,et al.  Effects of the substrate on the determination of thin film mechanical properties by nanoindentation , 2002 .

[61]  G. Pharr,et al.  An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments , 1992 .

[62]  William D. Nix,et al.  Analysis of the accuracy of the bulge test in determining the mechanical properties of thin films , 1992 .

[63]  William D. Nix,et al.  Mechanical properties of compositionally modulated Au-Ni thin films: Nanoindentation and microcantilever deflection experiments , 1994 .

[64]  S. M. Spearing,et al.  Materials issues in microelectromechanical systems (MEMS) , 2000 .

[65]  S. Cunningham,et al.  Elastic moduli, strength, and fracture initiation at sharp notches in etched single crystal silicon microstructures , 1999 .

[66]  B. S. Berry,et al.  Anelastic Relaxation in Crystalline Solids , 1972 .

[67]  W. Sharpe,et al.  Mechanical properties of MEMS materials , 2001, 2001 International Semiconductor Device Research Symposium. Symposium Proceedings (Cat. No.01EX497).

[68]  Reinoud F. Wolffenbuttel,et al.  Comparison of techniques for measuring both compressive and tensile stress in thin films , 1993 .

[69]  David T. Read,et al.  A new method for measuring the strength and ductility of thin films , 1993 .

[70]  T. Ikehara,et al.  New method for an accurate determination of residual strain in polycrystalline silicon films by analysing resonant frequencies of micromachined beams , 2001 .

[71]  L. B. Freund,et al.  Extensions of the Stoney formula for substrate curvature to configurations with thin substrates or large deformations , 1999 .

[72]  William D. Nix,et al.  Mechanical properties of thin films , 1989 .

[73]  Tong-Yi Zhang,et al.  Measurements of residual stresses in thin films using micro-rotating-structures , 1998 .

[74]  F. Ericson,et al.  Young's Modulus, Yield Strength and Fracture Strength of Microelements Determined by Tensile Testing , 1998 .

[75]  Wensyang Hsu,et al.  A microstructure for in situ determination of residual strain , 1999 .

[76]  Timothy A. Brunner,et al.  Elastic relationships in layered composite media with approximation for the case of thin films on a thick substrate , 1987 .

[77]  Tong-Yi Zhang,et al.  Microbridge testing of silicon nitride thin films deposited on silicon wafers , 2000 .

[78]  William N. Sharpe,et al.  Effect of specimen size on Young's modulus and fracture strength of polysilicon , 2001 .

[79]  D. W. Burns,et al.  A simple technique for the determination of mechanical strain in thin films with applications to polysilicon , 1985 .

[80]  P. Pimienta,et al.  Mechanical Properties , 2018, Bainite in Steels.

[81]  Brian D. Jensen,et al.  Interferometry of actuated microcantilevers to determine material properties and test structure nonidealities in MEMS , 2001 .

[82]  K. Petersen.  Dynamic micromechanics on silicon: Techniques and devices , 1978, IEEE Transactions on Electron Devices.

[83]  R. L. Edwards,et al.  Tensile testing of polysilicon , 1999 .