Mems unit 1-lec_1
- 2. PREVIEW • MEMS Introduction • Fabrication and Basic techniques • Applications • Advantages & Disadvantages • Future Trends • MEMS in India • Conclusion • References
- 3. • T echnology of Microscopic devices & miniaturized Integrated systems • Components 1 and 100 micrometres in size. • Devices 20 micrometres to a millimetre (i.e. 0.02 to 1.0 mm) • Micro-sized components assembled & working together as a system INTRODUCTION
- 4. Photo: http:// What are MEMS? Micro-Electro-Mechanical Systems (MEMS) • Miniaturized mechanical and electro-mechanical elements (devices and structures) • Sizes range from millimeters to fractions of micrometers • Some parts of the device have some sort of mechanical functionality • A.K.A. Microsystems Technology or Micromachined Devices
- 5. • Technique of combining Electrical & Mechanical disiciplines. • System of miniature dimensions. • Micro fabrication technologies. • Both sense on Micro scale effect on Macro scale • Control the environment. • Potential to effect all of our lives 5
- 6. Process flow • Design – Numerical • Coventorware, Intellisuite, COMSOL, ANSYS etc,. – Analytical • Fabrication • Assembling • Packaging • Testing – At die level – At packaging level 6
- 7. WHAT IS MEMS? 6 • Micro-electronics - Brain of the system. • Micro-sensors • Micro-actuator • Micro-structure - Arms ,eyes, nose etc. - Switch or trigger. -Micromachining
- 8. WHY MICROMACHINE • Minimize energy and mtrls use in manufacturing. • Integration with electronics, reduction of power budget. • Faster devices, incr selectivity and sensitivity. • Cost/Performance advantages. • Improved reproducibility (batch fabrication). • Improved accuracy and reliability. • Minimally invasive (e.g. pill camera).
- 9. SUBTRATES • Silicon • Glass • Polymers • Metals - Metals like Gold, Ni, Al, Cr, Pl, and Ag • Ceramics 12
- 10. 10 Why Silicon? • Not only a semiconductor • Very good structural material comparable with that of steel – Young’s modulus – Poisson’s ratio – Yield strength • Derives fabrication principles from well established Si based IC technology • Electronic circuits – Solid and compact • MEMS structures – holes, cavity, channels, cantilevers, membranes, etc,
- 11. FABRICATION 13 Basic Process Deposition Patterning Etching Chemical Wet Dry Physical Lithography Photolithography
- 12. BASIC PROCESS OF FABRICATION • Deposition – Deposition that happen because of a Chemical reaction or Physical reaction. • Patterning – Transfer to a photosensitive material, exposure to UV light. – Developed in solution after exposure to UV. – Material Etch away. • Etching – Strong acid to cut into the unprotected parts of a metal surface to create a design. – Two classes : • Wet Etching • Dry Etching. 14
- 16. DEPOSITION a) Physical Vapour Deposition. • Thin films one atom (or molecule) • Physical coating. • Deposition of aluminium or gold conductors. b) Chemical Vapour Deposition. • Volatile precursors on wafer react and/or decompose • High-purity, high-performance solid materials.
- 17. MEMS MANUFACTURING TECHNOLOGY 19 a) Bulk Micromachining. b) Surface Micromachining. c) High Aspect Ratio (HAR) Si Micromachining. • • LIGA SLIGA
- 18. LIGA 20 Lithographie (Lithography), Galvanoformung (Electroforming), & Abformung (Molding) • Additive Process • HARMST-High Aspect Ratio Microstructure Technology. • Precise dimensions and good surface roughness. • Output- Finished parts, molds, or stamps •SLIGA (Sacrificial LIGA). lower manufacturing infrastructures
- 19. LIGA Photo sensitive Material PMMA –Poly methyl metha crylate
- 20. PACKAGING a) Protection & robust to operating environment. b) Access and connections to physical domain. c) Minimize electrical interference. d) Dissipate heat for high operating temperatures. e) Minimize stress from external loading. f) Electric Power handling without signal disruption.
- 21. PACKAGING
- 22. MEMS APPLICATION MICRO NANO WORLD MEMS IN DEF BIO MEMS MICRO PROBING (STF,AFM) PRESSURE ,FORCE,INTERTIAL ,SOUNDS MICRO MAGNETICS RF MEMS MICRO FLUIDICS MICRO IT
- 23. MEMS ADVANTAGES IC COMPATIBLE LOW COST RUGGEDNESS SMALLER BATCH FABRICATION MINIATURIZATION LOW POWER CONSUMPTION HIGHER PERFORMANCE
- 24. DISADVANTAGES capabilities and manufacturing • Impossible to transfer of Power impossible. • Poly-Si (a brittle material), Cannot be load and force limitations. • Disruptive technology, need different competencies. • Scaling, Packaging and Testing Issues. • Challenges associated with developing processes. • Critical technological bottlenecks, economic feasibility. • Time & expense.
- 25. MEMS Sensors • Turn physical phenomena into measurable electrical signals • Most (if not all) incorporate circuitry/components to interpret electrical signals • Some have no moving parts
- 26. MEMS Sensors - Accelerometer
- 27. MEMS Sensors - Accelerometer
- 28. MEMS Sensors - Accelerometer
- 29. MEMS Sensors - Accelerometer Analog Output Accelerometer Module $2.70
- 30. MEMS Devices • Some are just scaled down versions of other systems • Use electric or electromagnetic principles to control mechanical effects • Commonly used in groups rather than individually
- 31. Some MEMS Applications Microchain Drive (Microchain & Gears)
- 32. FUTURE OF MEMS Challenges • Access to Foundries. • Design Simulation & Modelling • Packaging and Testing • Standardization • Education and Training. • Micro-sized objects allow us to go places where no objects have gone before.