Mechanics of Thin Films for Microsystem Design

Course IDCourse NameInstructorRoom NumbessrTime
ME6016Mechanics of Thin Films for Microsystem DesignRatna Kumar Annabattula; Manoj Pandey

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Course Contents

Introduction and fabrication: Introduction to thin film based micro systems; Growth of thin films; Oxidation: Deal Grove model; Patterning and etching; Developing process flow; Film microstructure and stress.

Deformation and failure mechanisms in thin films : Mechanical behaviour problems: wafer cracking, thin film debonding (blisters, varicose and telephone cord);

Sources of stresses in thin films: intrinsic (mis-fit), thermal and epitaxial, Stoney’s formula; Mechanics of thin films: Deflection associated with biaxial bending, film stress substrate curvature relations, thin film and substrate in a stress-free state

Dynamic aspects of thin film based structures : Lumped parameter based reduced order modeling of beams and plates; Scaling issues at micro scale and non-dimensionalization; Free and forced undamped vibrations, adding in-plane loads and effect of pre-stress; Mode-mixing; Modeling damping from squeeze film, thermoelastic effects and anchor loss; Anisotropic material response, Flexible (Non ideal) supports.

Applications: Modeling and analysis of a cantilever shaped RF MEMS switch; Reduced order model generation for a thin disc shaped MEMS oscillator; Dynamics of a thin circular plate under large deflection and mode mixing; One-dimensional blister problem for interfacial delamination; Self-forming of three-dimensional micron sized objects from planar (two-dimensional) thin films.

Text/Reference Books

1. Thin Film Materials: Stress, Defect Formation and Surface Evolution, L. B. Freund and S. Suresh, Cambridge University Press, ISBN-10:
0521822815, (2004).
2. Mechanical Properties of Thin Films (Lecture Notes), William D. Nix, Stanford University, Link: http://imechanica.org/node/530
3. Lecture notes on Fracture Mechanics of Thin Films and Composite Materials, J. W. Hutchinson and Z. Suo, Harvard University, Link: http://imechanica.org/node/754
4. Microsystem Design, Stephen D. Senturia, Springer, ISBN-10: 0792372468, (2000).
5. MEMS Linear and Nonlinear Statics and Dynamics (Microsystems), M. H. Younis, Springer, ISBN-10: 1441960198, (2011).