Micro Electro Mechanical Systems (MEMS) Class Materials - Lecture 02

Department of Instrumentation & Control Engineering, MIT, Manipal

Lecture #02

MEMS – An Overview

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Department of Instrumentation & Control Engineering, MIT, Manipal

Contents

1. Advantages and limitations

2. Applications

3. Visual Examples of MEMS Devices

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S.Meenatchisundaram, Department of Instrumentation & Control Engineering, MIT, Manipal

Advantages and limitations

Advantages:

� Small systems tend to move or stop more quickly due to low mechanical

inertia.

� It is thus ideal for precision movements and for rapid actuation.

� Miniaturized systems encounter less thermal distortion and mechanical

vibration due to low mass.

� Miniaturized devices are particularly suited for biomedical and aerospace

applications due to their minute sizes and weight.

� Small systems have higher dimensional stability at high temperature due

to low thermal expansion.

� Smaller size of the systems means less space requirements.

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S.Meenatchisundaram, Department of Instrumentation & Control Engineering, MIT, Manipal

Advantages and limitations

� This allows the packaging of more functional components in a single

device.

� Less material requirements mean low cost of production and transportation.

� Ready mass production in batches.

� Higher surface to volume ratio.

Limitations:

� Friction is greater than inertia. Capillary, electrostatic and atomic forces as

well as stiction at a micro-level can be significant.

� Heat dissipation is greater than heat storage and consequently thermal

transport properties could be a problem or, conversely, a great benefit.

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S.Meenatchisundaram, Department of Instrumentation & Control Engineering, MIT, Manipal

Advantages and limitations

� Fluidic or mass transport properties are extremely important. Tiny flow spaces

are prone to blockages but can conversely regulate fluid movement.

� Material properties (Young’s modulus, Poisson’s ratio, grain structure) and

mechanical theory (residual stress, wear and fatigue etc.) may be size dependent.

� Integration with on-chip circuitry is complex and device/domain specific. Lab-

on-a-chip systems components may not scale down comparably.

� Miniature device packaging and testing is not straightforward. Certain MEMS

sensors require environmental access as well as protection from other

external influences.

� Testing is not rapid and is expensive in comparison with conventional IC

devices.

� Cost – for the success of a MEMS device, it needs to leverage its IC batch

fabrication resources and be mass-produced. Hence mass-market drivers must

be found to generate the high volume production.5

• Automobile IndustryTire pressure sensor

Engine oil sensor

Combustion sensor

Fuel rail pressure sensor

• SafetyAir Bag Deployment system

Antilock braking systems

Navigation (micro gyroscope)

• Engine and power trainAirflow control

Fuel pump pressure and fuel injection control

Crankshaft positioning

• Health care IndustryDisposable blood pressure transducer (DPT)

Intrauterine pressure sensor (IUP)

Angioplasty pressure sensor

Infusion pump pressure sensor

Sphygmomanometer

Lung capacity meters

Kidney dialysis equipment

• Aerospace IndustryCockpit Instrumentation

Micro gyroscope

Micro satellite

• Industrial ProductsWater level controls

Refrigeration systems

Manufacturing process sensor

• Consumer productsSmart Toys

Sport shoes with automatic cushioning control

Washers with water level controls

Vacuum cleaning

• TelecommunicationsOptical switching and fiber-optic couplings

RF switches

Tunable resonators

Applications

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Applications

7S.Meenatchisundaram, Department of Instrumentation & Control Engineering, MIT, Manipal

Applications

8S.Meenatchisundaram, Department of Instrumentation & Control Engineering, MIT, Manipal

Applications

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Applications

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Applications

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Applications

12S.Meenatchisundaram, Department of Instrumentation & Control Engineering, MIT, Manipal

Applications

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Applications

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Applications

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Applications

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Applications

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Visual Examples

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Accelerometers

Visual Examples

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Micro Flying Robot

Visual Examples

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World’s Smallest Car

Visual Examples

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Visual Examples

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World’s Smallest Guitar

Visual Examples

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Pressure Sensors

Visual Examples

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LIGAGerman words for lithography, electroplating, and molding - High Aspect Ratio

Micromachining Technique

Low cost coplanar waveguide

Visual Examples

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