Intro to MEMS. Lecture 1: Dong-Il Dan Cho. Seoul National University Nano/Micro Systems & Controls Laboratory

Transcription

1 Lecture 1: Intro to MEMS School of Electrical l Engineering i and Computer Science, Seoul National University Nano/Micro Systems & Controls Laboratory dicho@snu.ac.kr URL:

2 What is MEMS? Different physics in nano and micro scales High viscosity (> inertia), stiction, friction & surface tension are dominant in micro world Antz, Dreamworks 2

3 What is MEMS? MicroElectroMechanical Systems The fabrication i of devices with at least some of their dimensions in the micrometer range. Increase performance and decrease cost. Application for electronics, communications, mechatronics, medicine, military Commercial product : an accelerometer sensor for the car air-bag, an inkjet printer header, a pressure sensor, components of RF and Optics As a new solution for IT, BT, ET, and NT many countries investment MEMS. 3

4 A brief MEMS history What is MEMS? 4

5 Scales and dimensions What is MEMS? 5

6 What is MEMS? Uses IC manufacturing techniques to fabricate moving structures in micro scale (Cornell) ( 6

7 What is MEMS? F = Scaling law 1 S 2 S 3 S 4 S As system becomes smaller, the scaling of the force also determines the acceleration, a; transit time, t; power per unit volume P/V O generated and dissipated the mass of a system : m, scales as (S 3 ) for generalized case with a force F scaling as (S F ) where x = distance S S S F F -3 S S S a = = [ S ][ S ] F = a = t = m S S S xm t = = ([ S ][ ][ ]) 1 S 3 S S S S -F 2 F -2.5 S P Fx -1 = V tv P S = O O S 0.5 V O 2 S 7

8 What is MEMS? Long slender beams are very strong in micro scale Nano/Micro Systems & Controls Lab, SNU But moving through air in micro scale is difficult (like swimming in molasses) 8

9 What are MEMS driving forces? Miniaturization Small feature: fast, precise, gentle, reach narrow space Wearable PC Multiplicity Batch fabrication: mass production, low cost Pre-assembled system and parallel processing: high density IBM Millipede Microelectronics Integration with electronic circuits 9

10 MEMS Market World MEMS market forecast Source: Inertial MEMS Markets For Consumer Electronics Applications 2007, Yole Developpement 10

11 Intro to Micromachining MEMS coined 1991 IOP JMM 1992 J of MEMS ~1995 SOI process 1988 UC Berkley micromotor: Beginning of the surface micromaching ADI accelerometer Cornell SCREAM process 1997 SNU SBM process Multi Chip Packaging

12 Intro to Bulk Micromachining (70 s) Anisotropic silicon etching Optical bench using (100) silicon Silicon tip using (111) silicon (SNU NML) 12

13 Intro to Surface Micromachining ( 85-95) Typical surface micromachining process steps In HF, oxide etches fast for sacrificial release substrate: (100), p- type substrate: (100), p- type (a) oxide/nitride deposition, polysilicon deposition & patterning (b) nitride deposition, sacrificial oxide deposition substrate: (100), p-type (c) anchor patterning, polysilicon deposition & patterning substrate: (100), p-type (d) sacrificial wet etch in HF (SNU MEMS MPC) 13

14 Intro to Surface Micromachining ( 85-95) Micro gear chain (four polysilicon) Actuated micromirrors (three polysilicon hinge structure) (Sandia Lab.) (UC Berkeley, Pister Ph.D. thesis) 14

15 Intro to Surface Micromachining ( 85-95) Aphid on mirror 6 gears (Sandia Lab.) 15

16 Applications Smart Sensors Smart sensor A sensor so with built-in intelligence The intelligence is partially or fully integrated on a single chip Measuring Sensing Element Smart sensor architecture Sensing element Interface element for signal conditioning and data conversion Processing element (this includes a microcontroller with an associated memory and software) Communication element Power source Signal Co ondition ning Power Energy Communication Micro ocontrolle er & Processor r 16

17 Applications Smart Sensors (cont d) Trend of the smart sensors Intelligence - Self identification Self diagnosis Self calibration Multi sensing Integration Signal Conditioning & Processing Miniaturization - Small scale - Integration - Nanotechnology Mechanical Thermal Performance - Accuracy Linearity Reliabilityy Maintenance free - Smart sensor system - Complex systems for sensing, transforming and signal processing Chemical Multi-Sensing Actuators Magnetic Radiant Electrical Standardization - Economies of scale - Importance of codes - Compatibility p y Current Trend in Sensors & Systems Smarter Cheaper g Integration 17

18 Applications Smart Sensors (cont d) Smart pressure sensors: piezoresistive or capacitive Sensor + Electronics Smaller & Cheaper Key trends The growth of the medical and automotive business is stable New application like the TPMS are boosting this market 2010 Battery less TPMS 1991? Bipolar integrated 2003 Smart pressure sensor 1999 (TPMS) CMOS integrated t (DSP) 1980 Uncompensated 1985 Temperature compensated 18

19 Applications Smart Sensors (cont d) Smart pressure sensors application Engine optimization, emission control, and safety enhancement Manifold intake air pressure (MAP) and barometric air pressure (BAP) for the engine control unit Tire pressure monitoring system (TPMS) and side airbag pressure sensor Medical applications Sleep apnea, asthma monitoring, blood pressure meter MAP sensor (Delphi) Airbag pressure sensor (Bosch) Wheel mounted TPMS (Siemens) Blood pressure meter (Motorola) 19

20 Applications Smart Sensors (cont d) Smart accelerometer: capacitive or thermal Smaller devices with multiple axis sensing Key trends The automotive business is increasing rapidly with the growth of ESP Consumer applications have really started use MEMS sensors in volume for application like mobile phone, GPS, and game controller Capacitive accelerometer (ADI) 2 chip accelerometer (Motorola) Dual-axis thermal accelerator (MEMSIC) 20

21 Applications Smart Sensors (cont d) Smart gyroscope : capacitive or piezoelectric Smaller devices with multiple axis sensing Key trends The ESP market is growing very fast, with adoption of the system in medium end cars. (Silicon vs. Quartz) GPS is another growth area, both for automotive and autonomous systems imems ADXRS (ADI) X-axis gyroscope (SNU, NML) Z-axis gyroscope (Motorola) 21

22 Applications Smart Sensors (cont d) Smart accelerometer & gyroscope applications Automotive: crash accident recording, ESP, GPS Consumer Electronics: video game controller, camera image stabilization, HDD protection, mobile phone, human computer interface Video game controller (Nintendo) Electronic Stability Program GPS Camera image stabilization (Sony) 22

23 Applications Smart Sensors (cont d) MEMS microphone Since 2004, the industry has seen increasing sales of MEMS devices across multiple consumer applications, with MEMS microphones for cell phones leading the pack. The market for overall MEMS microphones will be 432 million units in 2008, according to Yole report. MEMS microphone applications: mobile phone, PDA, digicam, camcorder, lab-top, automotive (hand-free calling) Silicon microphone (Knowles Acoustics) Surface mountable monolithic digital microphone & Fabrication process for MEMS microphone (Akustica) 23

24 Applications Smart Sensors (cont d) Smart biomedical sensors Biomedical sensors with integrated circuitry Implanted in the human body or wearable Will improve people s health, comfort and safety Typical future sensor node Example applications Glucose level monitor Transplant organ viability monitor Blood monitor Cancer detection/monitor Hand-Held Device Health monitor (receiver unit) Retinal and cortical prosthesis Wireless Body Area Network (WBAN) 24

25 Applications Fluidics and BioMEMS (cont d) DNA chip (Nanogen) Microfluidics (Twente) Micromixer (Micralyne) Nanopump (De GENEVE Univ.) Microneedle (NML SNU) DNA microarray chip(protron) 25

26 Applications Fluidics and BioMEMS (cont d) DNA chip (Roche) High through system (Caliper) Chemical Multiplexer (Aclara) Biosensor (IMEC ) 26

27 Applications Fluidics and BioMEMS (cont d) Neural Chip - The New Bionic Man Retina Implant Cochlear Implant Edinburgh Arm Heart Assist Pump Nose on a chip Electronic Tongue NCP (NeuroCybernetic Prosthesis) : relief for the epileptic seizures, VNS (Vagus Nerve Stimulation) Plastic muscle Silicon Sensor (Science, 8 February, 2002) 27

28 Applications Fluidics and BioMEMS (cont d) Cochlea prosthesis Cochlear Inc. 28

29 Applications Fluidics and BioMEMS (cont d) Vision prosthesis Extraocular Unit Intraocular Unit ( (Johns Hopkins University & North Carolina State University) 29

30 Applications Fluidics and BioMEMS (cont d) MEMS Neural probe (University of Michigan) (Sung June Kim, SNU) 30

31 Applications OMEMS (cont d) DLP(digital light processing) 31

32 Applications OMEMS (cont d) DLP(digital light processing) ( 32

33 Applications OMEMS (cont d) Microlens Microlenses array (Axetris) Micro-Lens Scanner (UC Berkeley) 33

34 Applications OMEMS (cont d) Optical switch 4 4 matrix switch for optical fiber switching Fast on/off optical switch (Neuchatel Univ.) (NML SNU) 34

35 Applications RF MEMS RF MEMS applications 35

36 Applications RF MEMS (cont d) RF MEMS components for wireless devices 36

37 Applications RF MEMS (cont d) Vibrating RF MEMS devices 60-MHz wine-glass disk resonator (Michigan) Filters Side-supported SCS disk resonator (Georgia Tech.) Quadrature mixer-filter (Michigan) Disk array composite µmechanical filter (Michigan) 37

38 Applications RF MEMS (cont d) MEMS switch Zipper-Actuated RF MEMS switch (MIT) Inductor Single crystalline silicon RF MEMS switch (SNU) Solenoid inductor (LG) 3-D microstructure for RF MEMS (KAIST) 38

39 Applications RF MEMS (cont d) Non-Contact-Type RF Switch (SNU) Free from welding and stiction problems RF characteristics of non-contact-type switch Insertion loss = GHz Isolation = GHz Off-state signal flow On-state signal flow The complete view of the switch The magnified view of the variable capacitors 39