MEMSMEMS

The DENSO Micro-Car is a miniature version of Toyota’s first passenger car. Fabricated using MEMS, at 1/1000 th the size of the original. It consists of a 0.67 mm magnetic-type working motor and when supplied with 3 V 20 mA of alternating current through a 18 m copper wire, μThe engine runs at 600 rpm equivalent to 5-6 mm/s

Micro-elctro-mechanical-systems is the technology of very small devices. MEMS can range in size from a few micrometers to millimetres.

It is a process technology used to create tiny integrated devices or systems that combine mechanical and electrical components.

MEMS are separate and distinct from the hypothetical vision of molecular nanotechnology.  

They usually consist of a central unit that processes data (the microprocessor) and several components that interact with the surroundings such as microsensors.

At these size scales, the standard constructs of classical physics are not always useful. Because of the large surface area to volume ratio of MEMS, surface effects such as electrostatics and wetting dominate over volume effects such as inertia or thermal mass.

APPLICATION AREAS

MEMS silicon motor together with a strand of human hair

Legs of a spider mite standing on gears from a micro-engine

The first commercial accelerometer from Analog

Devices (1990)

Lab-on-a-chip technology

● (a) Disposable blood pressure sensor connected to an IV line

● (b) disposable blood pressure sensors (as shipped)

● (c) intracardial catheter-tip sensors for monitoring blood pressure during shown on the head of a pin

MEMS optical cross connect consisting of an array of microscopic mirrors

COMMERCIALIZATION

Worldwide market size in 1996 and 2002 for existing MEMS product types in $US millions

Worldwide market size in 1996 and 2002 for emerging MEMS product types in $US millions

MEMS device complexity by structural layers

MEMS FABRICATION METHODS

● DEPOSITION PROCESSES

● ETCHING PROCESSES

● DIE PREPARATION

● HIGH-ASPECT-RATIO MICROMACHINING (HARM).

● SURFACE MICROMACHINING.

● BULK MICROMACHINING.

DEPOSITION PROCESSESPhysical depositionChemical deposition

PatterningLithography

PhotolithographyElectron beam lithography

Ion beam lithographyIon track technology

X-ray lithographyDiamond patterning

ETCHING PROCESSESWet etching

Isotropic etchingAnisotropic etching

HF etchingElectrochemical etching

Dry etchingVapor etching

Plasma etchingReactive ion etching (RIE)

INDUSTRY CHALLENGES● Limited access to MEMS fabrication facilities.

● Design, Simulation and Modelling.● Packaging and Testing.● Standardization.● Education and Training.