skt mems
TRANSCRIPT
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Shivaprasad K. Tilekar
Associate Professor
VLSI Design & Research Centre, Post Graduate Department of ElectronicsShankarrao Mohite Mahavidyalaya, Akluj, Dist. Solapur (MS)
Corresponding author: [email protected]
Dedicated to my guide
B. P. LadgaonkarProfessor & Head
Post graduate Department of ElectronicsShankarrao Mohite Mahavidyalaya, Akluj, Dist. Solapur (MS)
MicroElectroMechnical Systems(MEMS)
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Historical ApproachRichard Feynman "There's Plenty of Room at the Bottom”- Presentation given December 26, 1959 at California Institute of Technology- Tries to spur innovative miniature fabrication techniques for micromechanics- Fails to generate a fundamentally new fabrication technique
Westinghouse creates the "Resonant Gate FET" in 1969- microelectronics fabrication techniques-Invention of surface micromachining & use of sacrificial material to freemicromechanical devices from the silicon substrate.
Bulk-etched silicon wafers used as pressure sensors in 1970’s
Early experiments in surface-micromachined polysilicon in 1980’s- First electrostatic comb drive actuators- micropositioning disc drive heads
Micromachining leverages microelectronics industry in late 1980’s- Widespread experimentation and documentation increases public interest
Kurt Petersen published -Silicon as a Structural (Mechanical) Material in 1982- Reference for material properties and etching data for silicon
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a. Richard Feynman viewing the micromotor built by William McLellanb. Photograph of the motor 3.81 mm wide sitting beneath the head of pin
Feynman Challenge
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Production Engineering
Origin
Mechatronics Engineering• Micromechatronics• Nanomechatronics
Manufacturing Engineering
Micromanufacturing Engineering
• Microelectronics• MEMS
Nanomanufacturing Engineering
• Nanoelectronics• NEMS
Precision & Ultra precision Engineering
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Design, Fabrication & Testing
Scaling, Accuracy, Resolution and Repeatability
1. Micromilling : Cutting tool based & Focused Ion Based (FIB)
Spot size ~0.45um with 2.5 nA current and current density ~1.65 A/cm2
Typical milling rate 0.65um3/nA S. Average yield 6.5 atoms/ion.
2. Microdrilling:
Available 0.03-0.50 mm with increment of 0.01 mm.
Ultra Fast Pulse Laser Interface (PIL) technique
1. Si wafer- T: 0.54mm, Hole Diameter: 25um and Pitch: 50um
2. Al Niytide substrate T: 425um, Hole Diameter: ~290-300um
Precision Engineering Process
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Scaling
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Microlevel Scaling Issues
1. Friction is greater than inertia. Capillary, electrostatic and atomic forces as well
as stiction at a micro-level can be significant.
2. Heat dissipation is greater than heat storage and consequently thermal transport
properties could be a problem or, conversely, a great benefit.
3. Fluidic or mass transport properties are extremely important. Tiny flow spaces
may blockages or conversely may regulate fluid movement.
4. Material properties (Young’s modulus, Poisson’s ratio, etc.) and mechanical
theory (residual stress, wear, etc.) may be size dependent.
5. Integration with on-chip circuitry is complex and device/domain specific.
6. Miniature device packaging and testing is not straightforward.
7. Inexpensive – for the success of a MEMS device, it needs to leverage its IC batch
fabrication resources and be mass-produced.
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Importance of MST
• Minimize energy and materials use in manufacturing
• Redundancy and arrays
• Integration with electronics
• Reduction of power budget
• Faster devices
• Increased selectivity and sensitivity
• Exploitation of new effects through the breakdown of continuum theory
in the micro-domain
• Cost/performance advantages
• Improved reproducibility (batch fabrication)
• Improved accuracy and reliability
• Minimally invasive (e.g. pill camera)
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Classification of MST
Opt
ics
Electronics
MOES
MOEMS
MOMS MEMS
Mechanics
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Definition of MEMS
Micro - Small size, microfabricated structures
Electro - Electrical signal /control
Mechanical - Mechanical functionality
Systems - Structures, Devices, Systems- Control
The creation of 3-dimensional structures using integrated
circuits fabrication technologies and special micromachining processes.
Interdisciplinary Approach: IC Fabrication Technology, Mechanical
Engineering, Materials Science, Electrical Engineering, Chemistry and
Chemical Engineering, Fluid Engineering, Optics, Instrumentation and
Packaging.
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MEMS Devices
SemiconductorsInsulatorsDiodesTransistors
MEMS
ConductorsResistorsCapacitorsInductors
GearBearingDiaphragmPlatesCantileversBeamPostAnchorProbe etc.
Electronics, Electrical and Mechanical at MICRO LEVEL
Passive Electronic Systems & Passive Mechanical Systems
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MEMS Devices
MEMS
Microelectronics
MicrosensorsMicroactuators
Mechanical Microstructures
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Traditional Embedded Systems
Op amp
LP filter A/D Microcontroller
Op ampD/A
Sensor
Digital Outputs
LEDs
Competitive Solutions
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Recent Trend Embedded System
Op amp
LP filter A/D Microcontroller D/A
Sensor
Digital Outputs
LEDs
PSoC Microcontrollers
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Integrated embedded Microsystem
SensorElectronic
CircuitActuator
Micro Level
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MEMS Sensors
Based on Principles1. Thermoelectric2. Photoelectric3. Electromagnetic4. Magnetoelectric5. Thermoelastic6. Pyroelectric7. Thermomagnetic
Important Attributes1. Stimulus2. Specifications3. Physical Phenomenon4. Conversion Mechanism5. Material6. Response7. Ruggedness8. Stiffness9. Range10.Ability to measure parameters11. Application field
Measurable Parameters1. Temperature2. Pressure3. Humidity4. Flow5. Light Intensity6. Magnetic Field7. Vibration & so on
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MEMS in Automobile
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MEMS in BioMedical
Geographic ulceration suggestive of Barret'sEsophagus.
Pill Camera
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MEMS Actuators
Method Principle Power
Voltage
Current
Speed
Mechanical
Piezoelectric High 10-100 V
nA-uA mS
Thermal Galvanic High 1-10 V mA-10mA
mS
Electrostatic
Electrostatic Coulomb
Low 10-100 V
nA-uA uS
Magnetic Current Medium
1-5 V ~ 100mA
uS-mSInterfacing Components• Gear• Bearing• Diaphragm• Plates• Cantilevers• Beam• Post• Anchor• Probe etc.
On Movement• Translational• Rotational
Important Attributes1. Lightweight2. Conformable3. Precision4. Less Wear & Sticking
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Microelectronics
Deposition Chemical vapor deposition (CVD) Epitaxy Oxidation Evaporation Sputtering Spin-on methods
Etching Wet chemical etching
Istropic Anisotropic
Dry etching Plasma etch Reactive Ion etch (RIE, DRIE)
Patterning Photolithography X-ray lithography
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Mechanical MicroStructure
General Classification1. Bulk Micromachining2. Surface Micromachining3. High-Aspect-Ratio Micromachining (HARM)
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MicroStructure Cont…
Photolithography
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MicroStructure Cont…
Substrate: Si, Ge and GaAs
a. Abundant, inexpensive, and processed to unparalleled purity
b. Ability to be deposited in thin films is very amenable to MEMS
c. High definition and reproduction (high levels of MEMS precision)
d. Batch fabrication
Additive Films & Materials
a. Silicon - single crystal, polycrystalline and amorphous
b. Silicon compounds (SixNy, SiO2, SiC etc.)
c. Metals and metallic compounds (Au, Cu, Al, ZnO, GaAs, IrOx, CdS)
d. Ceramics (Al203 and more complex ceramic compounds)
e. Organics (diamond, polymers, enzymes, antibodies, DNA etc.)
Materials for Micromachining
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MicroStructure Cont…
Bulk Micromachining
Wet Etching (Liquid Phase) Substrate: Si or Quartz
To create large pits, grooves & channelsIsotropic Anisotropic(HNA) (KOH)
With agitation
Without agitation
MicroStructure Cont…
Bulk Micromachining
SiO2
p+ Si
<100> Sisubstrate
Pressure sensors
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MicroStructure Cont…
Bulk Micromachining
Dry Etching (Vapour Phase or Plasma-Based)
Substrate: Si, Plastic, Metal Ceramics
To create deep trenches & pits
Reactive Ion Etching
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MicroStructure Cont…
Surface MicromachiningDry Etching (Vapour Phase or Plasma-Based)
To create foundation layers
Reactive Ion Etching, Multi-User MEMS Procces (MUMP), Sandia Ultra
Planner Multi level Technology
Polysilicon micromotor Polysilicon resonator structure
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MicroStructure Cont…
Surface Micromachining
Fusion Bonding
Photoresist and PolyMethylMethAcrylate (PMMA)
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MicroStructure Cont…
High-Aspect Ratio Micromachining
Deep Reactive Ion Etching (DRIE)
Si
Glass
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MicroStructure Cont…
High-Aspect Ratio Micromachining
LIGA (a German acronym from Lithographie, Galvanoformung, Abformung translated as lithography, electroforming and moulding)
Other Technologies for HARMHot EmbossingLaser MicromachiningXeF2 Dry Phase EtchingElectro-Discharge MicromachiningFocused Ion Beam MicromachiningCAD Tool (MEMCAD)
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Assembly & System Integration
CAD design using MEMCAD from various vendors
Mask Generator
CAD Simulation & Modeling
Original Concept
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Applications
Controlling Micromanipulator, Microhandling Equipments, Microgrippers, Microrobots, etc.
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MEMS Market Forecast
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Challenges to MEMSIndustry
Access to Foundry
Design, Simulation and Moldelling
Packaging and Testing
Standardization
Education and Training
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MEMS Resources
Books
1. MEMS – N. P. Mahalik
2. Scaling Issues and Design of MEMS- S. Baglio, S. Castorina & N. Savalli
Websites
3. www.engineersgarage.com/articles/mems-technology
4. www.egr.msu.edu/classes/ece410/mason/files/MEMS%20overview.pdf
5. www.csa.com/discoveryguides/mems/overview.php
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Research Activities
Minor Research Projects : 01 Completed
(UGC Sponsored) : 01 OngoingPublications
: International Journals 05: National Journals 01: Proceedings International/National15
Papers presented in conferences: International 04: International (Abroad)01: National 46
Academic Talk : 06
THANK YOU