MEMS or Micro-Electro Mechanical System is a technique of combining Electrical and Mechanical components together on a chip, to produce a system of miniature dimensions. MEMS is the integration of a number of micro-components on a single chip which allows the microsystem to both sense and control the environment.
2. Outline
MEMS Introduction
Sensor and its type
Fabrication
MEMS Manufacturing Technology
Applications
Conclusion
References
3. What isMEMS?
MEMS or Micro-Electro Mechanical System is a
technique of combining Electrical and Mechanical
components together on a chip, to produce a system
of miniature dimensions.
MEMS is the integration of a number of micro-
components on a single chip which allows the
microsystem to both sense and control the
environment.
The components are integrated on a single chip
using micro fabrication technologies.
4. What isaSensor?
A device used to measure a physical quantity(such as
temperature) and convert it into an electronic signal of
some kind(e.g. a voltage), without modifying the
environment.
What can be sensed?
Almost Everything!!!
Commonly sensed parameters are:
Pressure
Temperature
Flow rate
Radiation
Chemicals
Pathogens
N
S
EW
2 Axis Magnetic
Sensor
2 Axis
Accelerometer
Light Intensity
Sensor
Humidity Sensor
Pressure Sensor
Temperature Sensor
5. But why MEMSfor sensors?
Smaller in size
Have lower power consumption
More sensitive to input variations
Cheaper due to mass production
Less invasive than larger devices
8. Basic Processof Fabrication
Deposition
Deposition that happen because of a chemical reaction or physical reaction.
Patterning
The pattern is transfer to a photosensitive material by selective exposure to a radiation source such as
light. If the resist is placed in a developer solution after selective exposure to a light source, it will etch
away.
Etching
Etching is the process of using strong acid to cut into the unprotected parts of a metal surface to create
a design in.
There are two classes of etching processes:
Wet Etching
Dry Etching.
10. MEMSManufacturing Technology
This technique involves the selective removal of the
substrate material in order to realize miniaturized
mechanical components.
A widely used bulk micromachining technique in
MEMS is chemical wet etching, which involves the
immersion of a substrate into a solution of reactive
chemical that will etch exposed regions of the
substrate at very high rates.
Bulk Micromachining
Etched grooves using
(a) Anisotropic etchants,
(b) Isotropic etchants,
(c) Reactive Ion Etching (RIE)
11. MEMSManufacturing Technology
In surface micromachining, the MEMS sensors are formed on top of the wafer
using deposited thin film materials.
Surface Micromachining
(a) Spacer layer deposition.
(b) Pattering of the spacer layer.
(c) Deposition of the microstructure layer.
(d) Patterning of desired structure.
(e) Stripping of the spacer layer resolves final
structure.
12. MEMSManufacturing Technology
HAR combines aspects of both surface and bulk
micromachining to allow for silicon structures with
extremely high aspect ratios through thick layers of
silicon (hundreds of nanometers, up to hundreds of
micrometers).
HAR MEMS technology enables a high degree of
immunity to high-frequency, high-amplitude parasitic
vibrations.
High Aspect Ratio (HAR) Silicon Micromachining
13. Applicationsin Medical Science
Biocavity Laser: This device distinguishes
cancerous from non cancerous cells thus aiding the
surgeons in operations.
Smart Pill :
Implanted in the body
Automatic drug delivery (on demand)
Sight forthe blind : MEMS based array that may be
inserted in the retina of a blind person to provide
partial sight
14. Applicationsin MarineScience
Sensing in marine environment maybe done for
various reasons:
Oil exploration and related applications
Global weather predictions
Monitor water quality for any contamination
Measure parameters detrimental to the “health” of
structures in the sea ( like oil rigs and ships )
Study of aquatic plants and animals
In military operations
15. Applicationsin MarineMilitary Operations
An array of MEMS sensors spread on the ocean
floor could detect the presence of enemy
submarines.
MEMS sensors (pressure sensors, accelerometers
etc.) are being used in anti-torpedo weapons on
submarines and ships.
MEMS sensors in torpedoes are responsible for
Detonating the torpedo at the right time
Hitting the target in a crowded environment
Prevent any premature explosion
16. CONCLUSION
MEMS promises to be an effective technique of producing sensors of high quality, at lower costs.
Thus we can conclude that the MEMS can create a proactive computing world, connected
computing nodes automatically, acquire and act on real-time data about a physical environment,
helping to improve lives, promoting a better understanding of the world and enabling people to
become more productive.
17. References
X. Wang, J. Engel, C. Liu, J. Micromech. Microeng. 2003, 13, 628.
Christian A. Zorman, Mehran Mehregany, MEMS Design and Fabrication, 2nd
Ed. 2,16.
Ms. Santoshi Gupta, MEMS and Nanotechnology IJSER, Vol 3, Issue 5,2012
Stephen Beeby, MEMS Mechanical Sensor, PP. 7
Lenz, J., Edelstein, A.S., "Magnetic sensors and their applications." IEEE Sensors J. 2006, 6,
631-649.
Sinclair M J 2000 A high force low area MEMS thermal actuator Proc. 7th Intersociety Conf. on
Thermal and Thermomechanical Phenomena (Las Vegas, NV) pp 127–32
R. Ghodssi, P. Lin (2011). MEMS Materials and Processes Handbook. Berlin: Springer.
Chang, Floy I. (1995).Gas-phase silicon micromachining with xenon difluoride. 2641. pp. 117.
Notes de l'éditeur
The question that arises in our mind is what is mems or micro elctro-mechanical system?
It is a technique of combining electrical and mechanical components together on a chip. It produce a system of miniature dimensions i.e the system having thickness less than the thickness of human hair. The components are integrated on a single chip using micro fabrication technology which allows the microsystem to both sense & control the environment.
Wet Etching: where the material is dissolved when immersed in a chemical solution.
Dry Etching: where the material is sputtered or dissolved using reactive ions or an etching agent.
The MEMS devices, in marine sensing maybe attached to:
Ships
Floating devices (buoys) in the sea
Fixed sea structures (like oil rigs)
Sea bed using links
AUVs(Autonomous Underwater Vehicle)