Micro and Smart Systems

Transcription

1 Micro and Smart Systems 1. G.K. Ananthasuresh, Mechanical Engineering,IISc 2. K.J. Vinoy, Electrical Communications Engineering, IISc, 3. S. Gopalakrishnan, Aerospace Engineering, IISc, 4. K.N. Bhat, Electrical Communications Engineering, IISc. Course coordinators Prof.K.N.Bhat, IISc Bangalore 1

2 Lecture Modules Module 1: Introduction - Lectures 1 to 6 Module 2: Microfabrication processes Lectures 7 to 14 Module 3: Mechanics of Solids - Lectures Module 4: Finite element method Lectures 25 to 30 Module 5: Electronics and packaging - Lectures 31 to 40 Prof.K.N.Bhat, IISc Bangalore 2

3 Text / References 1) S.D. Senturia, Microsustem Design, Kluwer Academic Publishers, ) Tai-Ran Hsu, MEMS & Microsystems Design and Manufacture, McGraw Hill, ) V.K. Varadan, K.J. Vinoy, and S. Gopalakrishnan, Smart Material Systems and MEMS: Design and Development Methodologies, Wiley, 2006 Suggested hyperlinks / Prof.K.N.Bhat, IISc Bangalore 3

4 Suggested Additional Readings 1) G.T.A. Kovacs, Micromachined Transducers Sourcebook, WCB McGraw-Hill, ) J.W. Gardner, Microsensors: principles and applications, John Wiley & Sons, ) M. Madou, Principles of Microfabrication, CRC Press, 1998 Prof.K.N.Bhat, IISc Bangalore 4

5 Micro and Smart Systems Lecture -1 Glimpses of Microsystems and Miniaturization Prof K.N.Bhat, ECE Department, IISc Bangalore Prof.K.N.Bhat, IISc Bangalore 5

6 What are MEMS and Micro Sytems? Micro Electro Mechanical Systems (MEMS ) are devices that have static or movable components with some dimensions on the scale of microns MEMS combine microelectronics and micromechanics, and sometimes micro-optics They are referred by different names in different countries MEMS : USA MicroSystems Technology (MST): Europe Micromachines : Japan Smart materials and Smart Structures: India Prof.K.N.Bhat, IISc Bangalore 6

7 Micro Electro Mechanical Systems (MEMS) - Microsystems This is a Revolution similar to VLSI in Microelectronics Deals with 1. Miniaturization and batch processing of Sensors, Actuators and microstructures 2. Integration of mechanical components with electronics Prof.K.N.Bhat, IISc Bangalore 7

8 Batch Processing and miniaturization Batch Processing Miniaturization Cost Reduction Reliability & Reproducibility Low Power operation Biomedical and aerospace Applications Prof.K.N.Bhat, IISc Bangalore 8

9 Miniaturization approaches Conventional Micromachining Silicon Micromachining Prof.K.N.Bhat, IISc Bangalore 9

10 Conventional Micromachining Techniques Each component must be made piece by piece. Low price for large production volumes are the result of mechanization. Ultrasonic machining, sandblasting, laser ablation and spark erosion have aided in miniaturization. Finest details that can be machined are one to two orders larger than what photolithography makes possible. Prof.K.N.Bhat, IISc Bangalore 10

11 Silicon Micromachining Suitable for batch processing similar to fabrication of ICs. Production costs of whole production is independent from number of components fabricated. Miniaturization with finest details in the range of 0.1 to 10 m possible based on photo-lithography Prof.K.N.Bhat, IISc Bangalore 11

12 Classification of MEMS MEMS structures and devices can be classified into four major groups: Passive (nonmoving) structures (eg) microtips Sensors, which respond to the world, (eg) pressure Actuators (reciprocal of the sensors), which use information to influence something in the world. (eg) pump, valve etc Micro-Systems that integrate both sensors and actuators to provide some useful function Prof.K.N.Bhat, IISc Bangalore 12

13 MEMS Categories and Application areas Application Areas Categories Transportation Communications Analytical & Medical MEMS Structures MEMS Sensors13 13 MEMS Actuators Infrared Imagers Pressure, Acceleration, & Angular Rate Aerodynamic Flow Control13 Optical & RF Signal Guides, Field Emission Arrays Acoustic sensors Displays, Optical switches, & RF Switches & Filters Micro Filters, Micro Channels & - Mixers Gas sensors Micro-pumps & -Valves Prof.K.N.Bhat, IISc Bangalore 13

14 Transducers Sensors Convert Measured Quantities into Electrical Signal Pressure sensor, Accelerometer, Gyro, Temperature Sensor, Gas sensor, Flow sensor Actuators Convert different types of energy into Mechanical Energy Micropump, RF switches and Resonators, micro mirror, ES comb drive Structures AFM tip, Field Emission Arrays, Micro-fluidic Channels Prof.K.N.Bhat, IISc Bangalore 14

15 Some Examples of Micromachined Miniaturized Mechanical component Micropump Pressure sensors Micro cantilevers (DNA Sensor) RF filters r k m Micro Acceleration Sensors F ma kx Nano- tip for AFM and for FEA Prof.K.N.Bhat, IISc Bangalore 15

16 Need for Miniaturization of Sensors 1.Intracranial Pressure (ICP) and blood pressure monitoring 3.Oceanography-CTD sensor for Marine Engg (NPOL, Kochin) 4. Air pressure and flow in the ignition system of automobile 2.Mapping pressure on LCA wing Prof.K.N.Bhat, IISc Bangalore 16

17 Piezoresistive pressure sensor Pressure P Diaphragm R1 R2 R3 R4 R Vo Sensitivity Piezo resistors : p-type boron diffused/ implanted R Vin R V S o P Prof.K.N.Bhat, IISc Bangalore 17

18 Motorola s Manifold-absolute Pressure (MAP) Sensor and schematic of its package Prof.K.N.Bhat, IISc Bangalore 18

19 Silicon cantilever beams for detection of DNA A hybrid micromachine /DNA system (IBM,Zurich) An array of cantilevers treated with different strands of DNA. When a solution containing different fragments of DNA is introduced, complementary strands of DNA will naturally bind to specific cantilevers creating stress which deflects the cantilever. Can detect damaged DNA sequences, since a single base mismatch will cause a slightly different stress, indicating the presence of a damaged fragment. Prof.K.N.Bhat, IISc Bangalore 19

20 Need for Miniaturization of structures Microstructures Field emission tips for high frequency Vacuum Electron Devices Micro geras Micro turbine Nanometer size AFM Tip Prof.K.N.Bhat, IISc Bangalore 20

21 Need for Miniaturization of Actuators Micropumps for l/minute pumping (1) Drug delivery drug dosage control (2) Lubricating bearings of gyro motor space appln. Pump Diaphragm Inlet Valve Actuation Mechanism Pump Chamber Outlet Valve Inlet Outlet Valve Threshold Pressure p (crit) Stroke Volume V Chamber Pressure p Chamber Volume Vo Prof.K.N.Bhat, IISc Bangalore 21

22 Microsystems and Miniaturization Miniaturization is important for Applications Biomedical : pressure sensors (Intra Cranial Pressure, blood pressure) ), cantilever beams (DNA analysis), micropump ( controlled micro dose of drug Delivery) Aerospace and Automobile: Pressure sensors, accelerometers, Space programs: Pressure sensors, accelerometers, gyro, micropump Micro fluidics channels and mixers: Chemical analysis and synthesis and lab on Chip concept Defense : Explosive detection, gas sensors, pressure sensors, acceleration sensors and RF MEMS Prof.K.N.Bhat, IISc Bangalore 22