A STUDY ON MEMS A STUDY ON MEMS RELIABILITY RELIABILITY
PRESENTED BYANIL BHARADWAJ.R
8TH SEMTCE DEPT
INSIDE
INTRODUCTION MEMS FABRICATION PROCESS DEPOSITION LITHOGRAPHY ETCHING MEMS FABRICATION TECHNIQUES BULK MICROMACHINING SURFACE MICROMACHINING MEMS RELIABILITY CONCLUSION
MEMS: MICRO ELECTRO MECHANICAL SYSTEM
SIZE OF MEMS DEVICES
RICHARD FEYNMAN
INTRODUCTION
CLEAN ROOM AND SILICON WAFER
Same as the process steps used for making conventional electronic circuits
MEMS PROCESS
FABRICATION PROCESS
DEPOSITION PROCESS
PHYSICAL VAPOR DEPOSITION
CHEMICAL VAPOR DEPOSITION
LITHOGRAPHY
Application of photo resist
Optical exposure to print an image of the mask onto the resist
Immersion in an aqueous developer solution to dissolve the exposed resist
ETCHING PROCESS
ETCHING IS PROCESS OF REMOVING UNPROTECTED PART
WET ETCH
DRY ETCH
ISTROPIC AND ANISOTROPIC
ISOTROPIC ETCHING GIVES UNIFORM ETCH RATE
ANISOTROPIC ETCHING GIVES NON UNIFORM ETCH RATE
MEMS FABRICATION TECHNIQUES
BULK MICROMACHINING
SURFACE MICROMACHINING
MEMS DEVICES
FAILURE MECHANISMS
MECHANICAL FRACTURECORROSIONSTICTIONWEARELECTRIC SHOT AND OPENCONTAMINATION
MECHANICAL FRACTURE
Mechanical fracture is local separation of an object or material into two or more pieces
CORROSION
Corrosion is disintegration of material into its constituent atoms due to chemical reactions with its surroundings
STICTION
WEAR
Wear is defined as the removal of material from a solid surface as the result of mechanical action
ELECTRICAL SHORT AND OPEN
THESE OCCURS DUE TO VARIOUS REASONS.
IT’S DIFFICULT TO IDENTIFY THESE KINDS OF FAULTS
CONTAMINATION
UNINTENTED MATERIAL
SOURCE FOR CONTAMINATION ARE MANY
IMPRECISE FABRICATION METHODS
EXPENSIVE AND COMPLEX PACKAGING
CAD DESIGN TOOL INACCURACIES
REASONS FOR FAILURE
APPLICATIONS OF MEMS
CONCLUSION
MEMS is an advancement over VLSI through its rugged and adaptable electro mechanical features.
Many mechanical and electro mechanical processes involved in Lithography, Deposition and Etching is reduced in MEMS over VLSI
Still the MEMS is fraught with some more mechanical and electro mechanical failures which can be overcome by understanding the mechanism and the physics underlying MEMS process more clearly.
So better understanding of failure mechanism of MEMS provides foundation for life time model.
REFERENCES
[1] R. M. Boysel, T. G. McDonald, G. A. Magel, G. C. Smith, and J. L. Leonard, “Integration of deformable mirror devices with optical fibers and waveguides,” in Proc. SPIE, 1992, vol. 1793, pp. 34–39.
[2] W. Kuehnel and S. Sherman, “A surface micromachined silicon accelerometer with on-chip detection circuitry,” Sens. Actuators A, Phys., vol. 45, no. 1, pp. 7–16, Oct. 1994.
[3] M. Younis, D. Jordy, and J. M. Pitarresi, “Computationally efficient approaches to characterize the dynamic response of microstructures under mechanical shock,” J. Mciroelectromech. Syst., vol. 16, no. 3, pp. 628– 638, Jun. 2007.
[4] ASM Handbook, vol. 13, “Corrosion,” ISBN 0-87170-007-7, ASM Int., Novelty, OH, 1987.
[5] W. van Arsdell and S. B. Brown, “Subcritical crack growth in siliconMEMS,” J.
Mciroelectromech. Syst., vol. 8, no. 3, pp. 319–327,Sep. 1999.
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