12.008-spring-2004 S.G. Kim 12.008 Design & Manufacturing IISpring 2004MEMS I2.008-spring-2004 S.G. Kim 2March 10th Ask “Dave” and “Pat” Petty money up to $200, Goggles Plant tour, April 21, 22, sign up! By 4/2 Quiz 1 on March 17th HW#4 due by Monday’s lecture 75 minutes (45 min) MEMS 1 today2.008-spring-2004 S.G. Kim 3Elephant vs. Ant Shock and impact Scale and form factor Load carrying capability Spider silk v.s. steel2.008-spring-2004 S.G. Kim 4Frog, Water Strider, Gecko2.008-spring-2004 S.G. Kimhttp://robotics.eecs.berkeley.edu/~ronf/GECKO/Figures/Hierarchy3.jpg5Never try to mimic the nature.e.g. Biomimetic researches.DNA~2-1/2 nm diameterThings Natural Things ManmadeMicroElectroMechanical devices10 -100 µm wideRed blood cellsPollen grainFly ash~ 10-20 µmAtoms of siliconspacing ~tenths of nmHead of a pin1-2 mmQuantum corral of 48 iron atoms on copper surfacepositioned one at a time with an STM tipCorral diameter 14 nmHuman hair~ 10-50 µm wideRed blood cellswith white cell~ 2-5 µmAnt~ 5 mmThe Scale of Things -- Nanometers and MoreDust mite200 µmATP synthase~10 nm diameterNanotube electrodeCarbon nanotube~2 nm diameterNanotube transistorOOOOOOOOO OOOOOSOSOSOSOSOSOSOSPOO21stCentury ChallengeCombine nanoscale building blocks to make novel functional devices, e.g., a photosynthetic reaction center with integral semiconductor storageThe Microworld0.1 nm1 nanometer (nm)0.01 µm10 nm0.1 µm100 nm1 micrometer (µm)0.01 mm10 µm0.1 mm100 µm1 millimeter (mm)1 cm10 mm10-2m10-3m10-4m10-5m10-6m10-7m10-8m10-9m10-10mVisibleThe Nanoworld1,000 nanometers = InfraredUltravioletMicrowaveSoft x-ray1,000,000 nanometers = Zone plate x-ray “lens”Outermost ring spacing~35 nmOffice of Basic Energy SciencesOffice of Science, U.S. DOEVersion 03-05-02DOE 200122.008-spring-2004 S.G. Kim 7Transition: Micro to Nano 20thCentury - Microelectronics and Information Technology Semiconductors, computers, and telecommunication 21stCentury - Limits of Microsystems Technology--- Nanotechnology Moore’s law Hard disc driveJohn Bardeen, Walter Brattain, and William Shockleyat Bell Laboratories, “First Transistor”2.008-spring-2004 S.G. Kim 8Moore’s LawYear of introduction Transistors4004 1971 2,2508008 1972 2,5008080 1974 5,0008086 1978 29,000286 1982 120,000386™ 1985 275,000486™ DX 1989 1,180,000Pentium® 1993 3,100,000Pentium II 1997 7,500,000Pentium III 1999 24,000,000Pentium 4 2000 42,000,000The number of transistors per chip doubles every 18 months. – Moore’s Law_ Rock’s Law2.008-spring-2004 S.G. Kim 9Microelectronics TechnologyTo meet the Moore’s Law,line width(1/2 pitch) requirement100 nm 200570 nm 200850 nm 201135 nm 2014The International Technology Roadmap for Semiconductors, 1999No solution yet, nanolithography?G-line:436nmI-line: 365nmDUV: 248 nm193 nmEUV2.008-spring-2004 S.G. Kim 10Aerial density, hard disk Superparamagnetic Effect“a point where the data bearing particles are so small that random atomic level vibrations present in all materials at room temperature can cause the bits to spontaneously flip their magnetic orientation, effectively erasing the recorded data. “2.008-spring-2004 S.G. Kim 11A DNA molecule is 2.5 nm wide.What is Nanotechnology?Nanomanufacturing?2.008-spring-2004 S.G. Kim 12Nano in ME Fluidics, heat transfer and energy conversion at the micro- and nanoscale Bio-micro-electromechanical systems (bio-MEMS) Optical-micro-electromechanical systems (optical-MEMS) Engineered nanomaterials Nano manufacturing Course 2A (Nanotrack)32.008-spring-2004 S.G. Kim 13MEMSMEMS MEMSTechnologiesOptical MEMSRF MEMSRF MEMSData StorageBio. MEMSPower MEMSMEMS for ConsumerElectronicsMEMS In SpaceMEMS for Nano.Courtesy: Sandia national laboratoryMaterialsProcessesSystemshttp://www.memsnet.org/mems/what-is.html2.008-spring-2004 S.G. Kim 14MEMS (Microelectromechanical Systems) Intergrated systems of sensing, actuation, communication, control,power, and computing Tiny, Cheaper, Less power New functions!!! (chemical, bio, µ-fluidic, optical, …)2.008-spring-2004 S.G. Kim 15Tiny Products DLP (Digital Micromirror Array)DLP106micromirrors, each 16µm2, ±10° tilt(Hornbeck, Texas Instruments DMD, 1990)TM2.008-spring-2004 S.G. Kim Analog Devices16Tiny Products Airbag sensors: Mechanical vs. MEMS2.008-spring-2004 S.G. Kim 17Tiny Products Airbag sensors: Mechanical vs. MEMS DLP (Digital Micromirror Array) DNA chip Optical MEMSSmalltimes, Vol.2 , no. 6, 2002Tiny Tech venture funding, 20022.008-spring-2004 S.G. Kim D. Kamen18Segway-Tilt-Rotation(Courtesy of Segway (r) Human Transporter (HT). Used with permission.)42.008-spring-2004 S.G. Kim 19Vibrating GyroscopeBy Charles Stark Draper LaboratoryBy Charles Stark Draper LaboratoryxzyCoriolisAcceleration2.008-spring-2004 S.G. Kim 20Electrostatic Comb Drive/sensing Paralle Plate Capacitor Capacitance=Q/V=ε A/dε Dielectric permittivity of air Electrostatic Force = ½ ε (A/d2).V2 Pull-in point: 2/3 ddK2.008-spring-2004 S.G. Kim 21Comb Drive C= ε A/d = 2n ε l h/d ∆C = 2n ε∆l h/d Electrostatic force Fel = ½ dC/dxV2 = n ε h/d V2∆ldVxl2.008-spring-2004 S.G. Kim 22Suspension mode failuresxyx2.008-spring-2004 S.G. Kim 23Comb Drive DesignsDC BiasAC Signal(180° phase shift)AC SignalGrating beamsFlexuresElectrostatic comb-driveslinearrotational2.008-spring-2004 S.G. Kim 24Capacitive Accelerometercapacitivesensorplatemassmeanderspring52.008-spring-2004 S.G. Kim 25Microfabrication process flow Single-mask process IC compatible Negligible residual stress Thermal budget Not yet packaged2.008-spring-2004 S.G. Kim 261) Begin with a bonded SOI wafer. Grow and etch a thin thermal oxide layer to act as a mask for the silicon etch.2) Etch the silicon device layer to exposethe buried oxide layer.3) Etch the buried oxide layer in buffered HF to release free-standing structures.Si device layer, 20 µm thickburied oxide layerSi handle waferoxide mask layersiliconThermal oxideSOI (Silicon on insulator)2.008-spring-2004 S.G. Kim G. Barbastathis & S. Kim27Surface micromachinedStructure 2 µmVertical stictionDRIE micromachinedStructure 10 µmLateral stiction300 µmNo stictionDRIE micromachinedStructure 10 µmProblems of fabrication2.008-spring-2004 S.G. Kim 28ADXL 50 accelerometerCapacitive sensingComb
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