mems reliability review

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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