Micro-Electromechanical System (MEMS)

K. Bharath Kanna, B.E MechProject Associate,NITTTR Chennai.

Introduction Micro-electromechanical systems

(MEMS) are small integrated devices or systems that combine electrical and mechanical components.

They range in size from the sub micrometer level to the millimetres level.

The legs of a spider mite standing on gears from a micro-engine.

A MEMS silicon motor together with a strand of human hair.

Different names for MEMS USA: Micro- Electro Mechanical

System. Europe: Micro system Technology. Japan: Micro machines.

MEMS Technology Micro fabrication Technology. The electronics are fabricated

using integrated circuit (IC) process sequences.

The micromechanical components are fabricated using compatible "micromachining" processes

Material Silicon Polymer Metals (gold, nickel, aluminum,

chromium, titanium, tungsten, platinum and silver)

Micro fabrication There are three basic building blocks in

MEMS technology. Deposition: The ability to deposit thin

film of material on substrate. Lithography: To apply a patterned mask

on top of the films by photolithographic imaging.

Etching: To etch the films selectively to the mask.

Deposition Technology Deposition technology can be

classified into two groups:Deposition by Chemical Reaction: Chemical Vapor Deposition. Electro deposition. Epitaxy Thermal oxidation.

Deposition TechnologyDeposition by Physical Reaction: Physical Vapor Deposition Casting

Lithography TechnologyLithography can be classified into

two groups: Pattern Transfer Lithographic Module

Etching TechnologyThere are two classifications for etching process:

Wet Etching: The material is dissolved in chemical solution.

Dry Etching: the material is sputtered or dissolved using reactive ions or vapour phase etchants.

Designing Process

Applications Pressure Sensor Accelerometers Inertial Sensors Micro engines

Commercial Application Inkjet printers Airbag Inflation system Tire Pressure Sensor Disposal Blood Pressure Sensor Dynamic Stability Control in Cars DMD chip in DLP Projectors

Advantages Minimize energy and materials use

in manufacturing Cost/performance advantages Improved reproducibility Improved accuracy and reliability Increased selectivity and

sensitivity

Disadvantages Farm establishment requires huge

investments Micro-components are Costly

compare to macro-components Design includes very much

complex procedures Prior knowledge is needed to

integrate MEMS devices

Thank You