微电子机械系统下一波硅革命

1、微电子机械系统下一波硅革命MEMS: the Next Wave Silicon Revolution,纲要,引言 什么是MEMS？ 为什么需要MEMS？ MEMS的发展历史(含动因) MEMS的基本原理？ 如何制作MEMS？ MEMS应用与产业？,Center of Sensors and Actuators, Institute of Electronic Engineering, China Academy of Engineering Physics,什么是MEMS？,Part 1,Center of Sensors and Actuators, Institute of Electr

2、onic Engineering, China Academy of Engineering Physics,Micro(small) Electro(electric components/functionality) Mechanical(mechanical components/functionality) Systems(integrated, system-like functionality),What are MEMS?,5,MEMS Defined,Micro ElectroMechanical Systems,Batch fabrication (e.g., IC tech

3、nology),Energy conversion: electrical to and from non-electrical,Ultimate goal: solutions to real problems, not just devices,English problems: plural or singular? Common oxymoron: “MEMS device” Why is batch fabrication a critical part of the definition?,MEMS Sensors,MEMS Actuators,Microsystems,Micro

4、systems, Wafer-level packaging System-in-package (SiP) Single-chip integration Compound materials Micro-injection molding of polymers “Nano” technologies, Wafer-level packaging System-in-package (SiP) Single-chip integration Compound materials Micro-injection molding of polymers “Nano” technologies,

5、MEMS Can:,7,Hear Talk Feel Move Fly Walk Grab Think,Sense See Control Pump Synthesize Align Cut More,8,MEMS Structures,Human hair (f 80-100mm),Silicon die (5 x 5 mm),MEMS,Pollen,Scales and Dimensions - MEMS,What are the issues? Fabrication (180 nm) Materials Physical mechanisms,MEMS cantilevers, bea

6、ms - “no wear out” Sliding; linear Rotating; partial, full, multi-plane Rotating Inter-contact; gears, wheels Hinges Ejectors; fluids, gas, solids Combinations,More on ACTUATION Later,MEMS Sensors,21,Motion Dongle,Motion sensor - Moto,Earthquake warn, power, fuel shutoff,Precise pedometers,Security,

7、Air Bag sensor - ADI,Game and computer input,JPL Micro-gyro,Military US Govt.,Vehicle; crash, roll-over, ride, mechanical wellness,Robots; movement,Military; vehicle, ordnance monitor,MEMS enabled iPhone,Motion-interactive,Complex MEMS Demo,22,Sandia National Laboratory,MEMS的发展历史(含动因),Part 3,Center

8、of Sensors and Actuators, Institute of Electronic Engineering, China Academy of Engineering Physics,24,A Brief History of MEMS:1. Feynmanns Vision,Richard Feynmann, Caltech (Nobel Prize, Physics, 1965)American Physical Society Meeting, December 29, 1959: “What I want to talk about is the problem of

9、manipulating and controlling things on a small scale. . In the year 2000, when they look back at this age, they will wonder why it was not until the year 1960 that anybody began seriously to move in this direction.” “ And I want to offer another prize - $1,000 to the first guy who makes an operating

10、 electric motor-a rotating electric motor which can be controlled from the outside and, not counting the lead-in wires, is only 1/64 inch cube.” he had to pay the electric motor prize only a year later ,25,2. Planar IC Technology,1958 Robert Noyce Fairchild and Jack Kilby (Nobel Prize, Physics, 2000

11、) -Texas Instruments invent the integrated circuit By the early 1960s, it was generally recognized that this was the way to make electronics small and cheaper,Harvey Nathanson and William Newell, surface-micromachined resonant gate transistor, Westinghouse, 1965 Did Harvey hear about Richard Feynman

12、s talk in 1959? I dont think so ,Why Didnt MEMS Take Off in 1965?,26,Resonant gate transistor was a poor on-chip frequency reference metals have a high temperature sensitivity and dont have a sharp resonance (low-Q) specific application didnt “fly” In 1968, Robert Newcomb (Stanford, now Maryland) pr

13、oposed and attempted to fabricate a surface micromachined electromagnetic motor after seeing the Westinghouse work Energy density scaling for this type of motor indicated performance degradation as dimensions were reduced Materials incompatibility with Stanfords Microelectronics Lab research focus o

14、n electronic devices became a major issue,Another Historical Current:Silicon Substrate (Bulk) Micromachining,27,1950s: silicon anisotropic etchants (e.g., KOH) discovered at Bell Labs Late 1960s: Honeywell and Philips commercialize piezoresistive pressure sensor utilizing a silicon membrane formed b

15、y anisotropic etching 1960s-70s: research at Stanford on implanted silicon pressure sensors (Jim Meindl), neural probes, and a wafer-scale gas chromatograph (both Jim Angell) 1980s: Kurt Petersen of IBM and ex-Stanford students Henry Allen, Jim Knutti, Steve Terry help initiate Silicon Valley “silic

16、on microsensor and microstructures” industry 1990s: silicon ink-jet print heads become a commodity,When the Time is Right ,28,Early 1980s: Berkeley and Wisconsin demonstrate polysilicon structural layers and oxide sacrificial layers rebirth of surface micromachining 1984: integration of polysilicon

17、microstructures with NMOS electronics 1987: Berkeley and Bell Labs demonstrate polysilicon surface micromechanisms; MEMS becomes the name in U.S.; Analog Devices begins accelerometer project 1988: Berkeley demonstrates electrostatic micromotor, stimulating major interest in Europe, Japan, and U.S.;

18、Berkeley demonstrates the electrostatic comb drive,29,Polysilicon Microstructures,UC Berkeley 1981-82,R. T. Howe and R. S. Muller, ECS Spring Mtg., May 1982,Polysilicon MEMS + NMOS Integration,30,UC Berkeley 1983-1984,R. T. Howe and R. S. Muller, IEEE IEDM, San Francisco, December 1984,Transresistan

19、ce amplifier,Capacitively driven and sensed 150 m-long polysilicon microbridge,Polysilicon Electrostatic Micromotor,31,Self-aligned pin-joint, madepossible by conformal depositionof structural and sacrificial layers Prof. Mehran Mehregany, Case Western Reserve Univ.,Electrostatic Comb-Drive Resonato

20、rs,32,W. C. Tang and R. T. Howe, BSAC 1987-1988,New idea: structures move laterally to surface,C. Nguyen and R. T. Howe, IEEE IEDM, Washington, D.C., December 1993,Analog Devices Accelerometers,33,Integration with BiMOS linear technology Lateral structures with interdigitated parallel-plate sense/fe

21、edback capacitors,ADXL-05 (1995) Courtesy of Kevin Chau, Micromachined Products Division, Cambridge,Surface Micromachining Foundries,34,M. S. Rodgers and J. Sniegowski, Transducers 99 (Sandia Natl. Labs),1. MCNC MUMPS technology (imported from Berkeley) 1992- 2. Sandia SUMMiT-IV and -V technologies:

22、 1998 4 and 5 poly-Si level processes result: more universities, companies do MEMS,Self-Assembly Processes,35,Prof. J. Stephen Smith, UC Berkeley EECS Dept.,Alien Technologies, Gilroy, Calif. chemically micromachined“nanoblock” silicon CMOS chiplets fall into minimum energy sites on substrate,nanobl

23、ocks being fluidically self-assembed into embossed micro-pockets in plastic antenna substrate,MEMS的基本原理？,Part 4,Center of Sensors and Actuators, Institute of Electronic Engineering, China Academy of Engineering Physics,Cantilevers are used as Sensors Cantilevers are used as Switches Many MEMS Sensor

24、s use the principles of Cantilevers as well as RF Swtiches,MEMS Cantilevers,Cantilevers have a resonant frequency that depends on the length and the mass.,What is a Cantilever?,MEMS cantilevers as biosensors,MEMS Cantilever sensors,The ends of the cantilevers are coated with a layer of probe molecul

25、es. When a target molecule is present, it attaches to the probe molecule, thereby increasing the mass. The resonant frequency goes down. You just detected the presence of a molecule!,A gold dot, about 50 nanometers in diameter, fused to the end of a cantilevered oscillator about 4 micrometers long.

26、A one-molecule-thick layer of a sulfur-containing chemical deposited on the gold adds a mass of about 6 attograms (10-18 grams) , which is more than enough to measure. Craighead Group/Cornell Univeristy,As mass is added to the cantilever shifts the resonance frequency.,Cantilever Sensors,Resonance S

27、hift,5 x 15um Cantilever with an E. Coli cell bound to antibody layer.,Black is the response before cell attachment, Red is after cell attachment.,/releases/April04/attograms.ws.html,Resonance Shift due to Single Cell,Resonance Frequency Shift as a Function of Mass,Detectio

28、n of Single DNA,/Nems%20Folder/Enumeration%20of%20Single%20DNA.html,By changing the coating (Nano) one can functionalize the cantilever to detect single strands of DNA. Mass resolution is on the order of under 1 ato gram (10-18grams),Gold dot = 40nm SiN thickness = 90nm,Elec

29、trical actuation of active MEMS devices,如何制作MEMS？,Part 5,Center of Sensors and Actuators, Institute of Electronic Engineering, China Academy of Engineering Physics,MEMS三类工艺的比喻,体微加工(Bulk Micromachining) 表面微加工(Surface Micromachining) LIGA微加工(LIGA Micromachining),干法刻蚀,牺牲层,模铸,Surface Micromachining: Lay

30、er by layer addition,Starting from bare silicon wafer, deposit & pattern multiple layers to form a (shippable) MEMS wafer,From Cronos/JDSU MUMPS user guide at www.MEMSRUS.com,Assembly = mechanical manipulation of structures (e.g., raising and latching a vertical mirror plate) Various techniques used

31、, some highly proprietary,Surface Micromachining,Mechanical structures formed on the surface of a substrate. Formed from materials deposited on the substrate. Most common method of surface micromachining is known as Sacrificial Layer Technology. Additive process growing / depositing layers of materi

32、als, patterning and selectively removing them,Silicon,Silicon Nitride,Silicon Dioxide,Wet etch,Example on silicon:,Surface Micromachining (2),MEMS Folks like bugs?!,Bulk MEMS Fabrication: Pattern & selective etch,(2) DRIE vertical etch,“Bulk Silicon” MEMS Devices,Comb-drive switch photo courtesy IMT

33、 (Neuchatel),Single-axis tilt-mirror photo courtesy R. Conant, BSAC,In the early 1980s Karlsruhe Nuclear Research Center in Germany developed LIGA LIGA is a German acronym for X-ray lithography (X-ray Lithographie), Electroplating (Galvanoformung), and Molding (Abformung) It allows for manufacturing

34、 of high aspect ratio microstructures High aspect ratio structures are very skinny and tall LIGA structures have precise dimensions and good surface roughness,Microfluidic device made using LIGA process,1982 LIGA Process Introduced,Capacitive Comb drive also made using the LIGA process,LIGA 是一种高深宽比（

35、high aspect ratio）微结构加工技术，主要有三个步骤 X-射线光刻 (LI = Lithographie，德文) 利用同步辐射生成光刻胶的微结构雏形 DXRL = deep x-ray lithography 深X射线光刻 UDXRL = ultra-deep x-ray lithography 超深X射线光刻 电铸 (G = Galvanik) 形成金属微结构 成型 (A = Abformung) 二次微结构，可以用聚合物、金属、陶瓷等材料 1980年代德国Karlsruhe研究中心开发 极高深宽比 (可达100)、极小(亚微米)、极厚（3mm）微结构，侧壁极光滑 (表面粗糙度

36、 30 nm)、极垂直1um/1000 um 工艺类型 : 基本 LIGA SLIGA (牺牲层LIGA) 沉积牺牲层以释放结构 LIGA-like 准LIGA用Polyimide替代PMMA或用UV替代X-射线曝光,什么是 LIGA？,Synchrotron radiation is an electromagnetic radiation (light) emitted from electrons (positrons) moving with relativistic velocities on macroscopic circular orbits.,What is SR (Sync

37、hrotron Radiation)?,基本LIGA工艺,Lithography/Electroplating/Plastic molding,聚合物结构复制,光刻,金属化,后处理,电铸,翻铸成形,金属翻铸,LIGA样品,倾斜与旋转曝光,62,Microassembly Processes,Parallel assembly processes promise inexpensive, high-volume hetero-geneous integration of MEMS, CMOS, and photonics,Parallel Pick-and-Place, Chris Keller

38、, Ph.D. MSE 1998,Michael Cohn, Ph.D. EECS, 1997,Fluidic Self-assembly,Uthara Srinivasan, Ph.D., Chem.Eng. 2001,Wafer-LevelBatchAssembly,Many challenges: interconnect glue,MEMS 和封装,电子器件封装 保护电子芯片、提供电连接 晶圆裂解成为芯片, 安装到陶瓷或塑料管壳内 Single package, many chips MEMS封装 提供与外部环境的电和其它（流体、光等）连接、保护微机械单元 结构释放之前不能裂解芯片 封

39、装内环境非常重要 封装不会给MEMS器件带来新的应力问题 Single chip, many packages 对MEMS设计而言，封装、测试和标定更为重要,现有MEMS封装,MEMS reliability?,Conclusions: (1) Properly designed MEMS devices are remarkably shock resistant (2) Flexural failures due to fatigue were not apparent (3) Rubbing wear (& resulting debris) was their primary fail

40、ure mechanism,40,000G impact test Ceramic package destroyed MEMS survives (!),Micromotor test device Comb-drive actuator Flexural contact to gears,Failure by rubbing contact Wear on silicon surface Submicron particles generated,“MEMS Reliability: Infrastructure, Test Structures, Experiments and Fail

41、ure Modes” 171 page report by D. M. Tanner et al, SAND2000-0091, January 2000.,,MEMS应用与产业？,Part 6,Center of Sensors and Actuators, Institute of Electronic Engineering, China Academy of Engineering Physics,Mass commercial application: Pressure Sensors,Capacitive Pressure Sensor,Silicon

42、substrate,Pint,Pext,Spacer,Membrane,Force,Measure RC time,NovaSensors piezo-resistive pressure sensors,Disposable medical sensor,High-pressure gas sensor (ceramic surface-mount),Piezo-resistive pressure sensor,Pressure sensors utilise an thin membrane formed on or in the silicon chip.,Pressure,Sensi

43、ng mechanism detects the movement of the diaphragm. Signal conditioning electronics integrated on the same die.,Photo from GE Novasensor Catheter pressure sensors,Pressure Sensors,Disposable Blood Pressure Sensors,Disposable sensors use MEMS transducers to measure changes in blood pressure. Photo co

44、urtesy of Motorola, Sensor Products Div., Phoenix, AZ.,These $10 devices connect to a patients IV line and monitor blood pressure through the IV solution.,Atomic Force Microscope,Sensors: Mechanical Measurement,Ink Jet,Ink jet printers are MEMS based 1979 IBM and HP,Ink jet printers are MEMS based 1

45、979 IBM and HP,Ink Jet,1979 HP Micromachined Inkjet Nozzle,Schematic of an array of inkjet nozzles.,Close-up view of a commercial inkjet printer head illustrating the nozzles.,This printing technique rapidly heats ink, creating tiny bubbles. When the bubbles collapse, the ink squirts through an arra

46、y of nozzles onto paper and other media. Silicon micromachining technology is used to manufacture the nozzles. The nozzles can be made very small and can be densely packed for high resolution printing.,Ink Jet,Ink jet printers are MEMS based late 1970s, IBM and HP,Automotive MEMS,MEMS Sensors and Ac

47、tuators used to control various elements of the automobile Powertrain and Chassis control Ex: Manifold Air Temperature Comfort and Convenience Ex: Air-Temperature Control Communications Ex: Wireless,Automotive MEMS Summary,Precision Engineering By V. C. Venkatesh, Sudin Izman,Where it Began,1979 - F

48、irst recorded use of MEMs in automobiles Federal emission standards required monitoring the air-to-fuel ratio of the engine Density of air value was needed Many different sensor technologies were introduced to solve this problem MAP (manifold absolute pressure) and MAT (manifold air temperature) sen

49、sors were developed using MEMS Silicon based MEMS sensors became the device of choice due to low cost and high yield,Who Developed It,Two groups Delco Electronics Group(General Motors) Used piezoresistive sensing Ford Used capacitive sensing,MEMS as Machines,MEMS are often referred to as Micro Machi

50、nes. Tiny devices that move things.,Gear Train. Each gear tooth is 8 microns wide.,Mirror (popped up),Micro Machines,Surface Micromachining takes off in the 1990s. Sandia National Laboratories,This basically consists of alternating layers of structural materials (polycrystalline silicon) and sacrifi

51、cial layers (Silicon Dioxide). The sacrificial layer is a scaffold and acts as a temporary support and spacing material. The last step of the process is the “release” step, where the sacrificial layer is removed freeing the structural layers so they can move.,In this image, the square at the top is

52、a microfluidics device with internal passageways used for a lab on a chip. The multi-arm device (center) is a fuel injection nozzle. Bottom left is an accelerometer, and bottom right is an inductor used in RF circuits. (Image courtesy of Microfabrica Inc., .),Micromachines,In this image, the square

53、at the top is a microfluidics device with internal passageways used for a lab on a chip. The multi-arm device (center) is a fuel injection nozzle. Bottom left is an accelerometer, and bottom right is an inductor used in RF circuits. (Image courtesy of Microfabrica Inc., .),Micromachines,Microfluidic

54、s Device,In this image, the square at the top is a microfluidics device with internal passageways used for a lab on a chip. The multi-arm device (center) is a fuel injection nozzle. Bottom left is an accelerometer, and bottom right is an inductor used in RF circuits. (Image courtesy of Microfabrica

55、Inc., .),Micromachines,Fuel Injection Nozzle,Microfluidics Device,In this image, the square at the top is a microfluidics device with internal passageways used for a lab on a chip. The multi-arm device (center) is a fuel injection nozzle. Bottom left is an accelerometer, and bottom right is an induc

56、tor used in RF circuits. (Image courtesy of Microfabrica Inc., .),Micromachines,Accelerometer,Fuel Injection Nozzle,Microfluidics Device,In this image, the square at the top is a microfluidics device with internal passageways used for a lab on a chip. The multi-arm device (center) is a fuel injectio

57、n nozzle. Bottom left is an accelerometer, and bottom right is an inductor used in RF circuits. (Image courtesy of Microfabrica Inc., .),Micromachines,Accelerometer,Fuel Injection Nozzle,Microfluidics Device,Inductor,87,Experimental Catheter-type Micromachine for Repair in Narrow Complex Areas,Japan

58、ese Micromachine Project 1991-2000,Hybrid Insect-Micro Electro-Mechanical Systems,Hybrid Insect-Micro Electro-Mechanical Systems,Roboroach (2001) Roborat (2002) Brain chips for quadriplegics And now HI-MEMS,MAV例,U.of Florida-MAV 2001,7 inch, Engine,MicroSTAR (Lockheed Martin) 6in, 85g, E. Motor,Blac

59、k Widow (Aerovironment) 6.0 in, 80g, E. Motor,BYU-MAV 2002,4.75 inch, E. Motor Without Camera,全球主流MEMS厂商,美国：德州仪器公司(TI) 、模拟器件公司(ADI)、飞思卡尔半导体公司(Freescale)、Kionix公司、Akustica公司、Knowles Acoustics公司、SiTime公司、惠普公司、IMT公司、Silicon Microstructures公司(SMI)、GE Infrastructure Sensing公司； 欧洲：Robert Bosch公司、意法半导体公司(ST)、VTI科技公司、声扬公司(Sonion MEMS A/S)、Measurement Specialties公司(MSI)、Colibrys公司、Memscap公司、Tronics Microsystems公司； 日本：丰田电装DENSO公司、欧姆龙公司(Omron)、Matsushita公司、