Skt mems
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The document provides an overview of microelectromechanical systems (MEMS) technology. It discusses key events in the development of MEMS such as Richard Feynman's 1959 talk on miniaturization and the invention of surface micromachining in the 1980s. The document then covers various MEMS fabrication techniques including lithography, deposition, etching, and bonding. It also describes different types of micromachining like bulk, surface, and high-aspect ratio micromachining. Finally, the challenges, applications, and future of MEMS are briefly discussed.
Skt mems
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- 2. Shivaprasad K. Tilekar Associate Professor VLSI Design & Research Centre, Post Graduate Department of Electronics Shankarrao Mohite Mahavidyalaya, Akluj, Dist. Solapur (MS) Corresponding author: t_shivaprasad@rediffmail.com Dedicated to my guide B. P. Ladgaonkar Professor & Head Post graduate Department of Electronics Shankarrao Mohite Mahavidyalaya, Akluj, Dist. Solapur (MS) 2
- 3. 3 Richard 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 free micromechanical 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
- 4. a. Richard Feynman viewing the micromotor built by William McLellan b. Photograph of the motor 3.81 mm wide sitting beneath the head of pin 4
- 5. Production Engineering 5 Mechatronics Engineering • Micromechatronics • Nanomechatronics Manufacturing Engineering Micromanufacturing Engineering • Microelectronics • MEMS Nanomanufacturing Engineering • Nanoelectronics • NEMS Precision & Ultra precision Engineering
- 6. 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 6
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- 8. 8 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.
- 9. 9 • 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)
- 11. Micro - Small size, microfabricated structures Electro - Electrical signal /control Mechanical - Mechanical functionality Systems - Structures, Devices, Systems- Control 11 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.
- 12. 12 Semiconductors Insulators Diodes Transistors MEMS Conductors Resistors Capacitors Inductors Gear Bearing Diaphragm Plates Cantilevers Beam Post Anchor Probe etc. Electronics, Electrical and Mechanical at MICRO LEVEL Passive Electronic Systems & Passive Mechanical Systems
- 14. Op amp LP filter A/D Microcontroller Op ampD/A Sensor Digital Outputs LEDs Competitive Solutions 14
- 15. Op amp LP filter A/D Microcontroller D/A Sensor Digital Outputs LEDs PSoC Microcontrollers 15
- 17. 17 Based on Principles 1. Thermoelectric 2. Photoelectric 3. Electromagnetic 4. Magnetoelectric 5. Thermoelastic 6. Pyroelectric 7. Thermomagnetic Important Attributes 1. Stimulus 2. Specifications 3. Physical Phenomenon 4. Conversion Mechanism 5. Material 6. Response 7. Ruggedness 8. Stiffness 9. Range 10.Ability to measure parameters 11.Application field Measurable Parameters 1. Temperature 2. Pressure 3. Humidity 4. Flow 5. Light Intensity 6. Magnetic Field 7. Vibration & so on
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- 19. 19 Geographic ulceration suggestive of Barret's Esophagus. Pill Camera
- 20. 20 Method Principle Powe r Voltage Current Speed Mechanical Piezoelectric High 10-100 V nA-uA mS Thermal Galvanic High 1-10 V mA- 10mA mS Electrostati c Electrostatic Coulomb Low 10-100 V nA-uA uS Magnetic Current Medi um 1-5 V ~ 100mA uS-mS Interfacing Components • Gear • Bearing • Diaphragm • Plates • Cantilevers • Beam • Post • Anchor • Probe etc. On Movement • Translational • Rotational Important Attributes 1. Lightweight 2. Conformable 3. Precision 4. Less Wear & Sticking
- 21. 21 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
- 22. 22 General Classification 1. Bulk Micromachining 2. Surface Micromachining 3. High-Aspect-Ratio Micromachining (HARM)
- 24. 24 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
- 25. 25 Bulk Micromachining Wet Etching (Liquid Phase) Substrate: Si or Quartz To create large pits, grooves & channels Isotropic Anisotropic (HNA) (KOH) With agitation Without agitation
- 26. Bulk Micromachining SiO2 p+ Si <100> Si substrate Pressure sensors
- 27. 27 Bulk Micromachining Dry Etching (Vapour Phase or Plasma-Based) Substrate: Si, Plastic, Metal Ceramics To create deep trenches & pits Reactive Ion Etching
- 28. 28 Surface Micromachining Dry 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
- 29. 29 Surface Micromachining Fusion Bonding Photoresist and PolyMethylMethAcrylate (PMMA)
- 30. 30 High-Aspect Ratio Micromachining Deep Reactive Ion Etching (DRIE) Si Glass
- 31. 31 High-Aspect Ratio Micromachining LIGA (a German acronym from Lithographie, Galvanoformung, Abformung translated as lithography, electroforming and moulding) Other Technologies for HARM Hot Embossing Laser Micromachining XeF2 Dry Phase Etching Electro-Discharge Micromachining Focused Ion Beam Micromachining CAD Tool (MEMCAD)
- 32. 32 CAD design using MEMCAD from various vendors Mask Generator CAD Simulation & Modeling Original Concept
- 33. 33 Controlling Micromanipulator, Microhandling Equipments, Microgrippers, Microrobots, etc.
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- 35. 35 Access to Foundry Design, Simulation and Moldelling Packaging and Testing Standardization Education and Training
- 36. 36 Books 1. MEMS – N. P. Mahalik 2. Scaling Issues and Design of MEMS- S. Baglio, S. Castorina & N. Savalli Websites 1. www.engineersgarage.com/articles/mems-technology 2. www.egr.msu.edu/classes/ece410/mason/files/MEMS%20overview.pdf 3. www.csa.com/discoveryguides/mems/overview.php
- 37. Research Activities Minor Research Projects : 01 Completed (UGC Sponsored) : 01 Ongoing Publications : International Journals 05 : National Journals 01 : Proceedings International/National 15 Papers presented in conferences : International 04 : International (Abroad) 01 : National 46 Academic Talk : 06 37