Lecture 0 Lecture 0 MEMS (Microelectromechanical Systems) : MEMS (Microelectromechanical Systems) : The Leading Technology in the 21st Century The Leading Technology in the 21st Century

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Lecture 0 Lecture 0

MEMS (Microelectromechanical Systems) : MEMS (Microelectromechanical Systems) : The Leading Technology in the 21st Century The Leading Technology in the 21st Century

• Introduction

• Applications

– Micro inertial sensors – Display devices

– Information storage devices

– MEMS-based RF communication devices

마이크로시스템 기술 개론 MEMS_Lect00_1

– Micro chemical testing systems

• Conclusions

What is MEMS ? What is MEMS ?

Microelectromechanical systems (MEMS) are integrated micro devices or systems combining electrical and mechanical components fabricated using integrated circuit (IC) compatible batch-processing techniques and range in size from micrometers to millimeters. Current MEMS applications include

l t h i l d fl i ti ti l

accelerometers, pressure, chemical, and flow sensors, micro-optics, optical scanners, and fluid pumps. MCNC, North Carolina

Vibrating micro gyroscope

130㎛

5㎛ 130㎛

5㎛

Thick PR mold for Electroplating

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Fabrication Process of Micro Cantilever Fabrication Process of Micro Cantilever

Insulator Etch Mask

(a)

(b)

(d)

(e) Sacrificial layer

Structure layer

(c) (f)

Insulator Sacrificial layer Structure layer Etch Mask

Microfabricated Gear Microfabricated Gear

A tick is on a 300- micrometer diameter gear.

From Sandia National Laboratories

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Conventional vs. MEMS Inertial Measurement Conventional vs. MEMS Inertial Measurement

Units Units

From DARPA

Mass Spectrograph on a Chip Mass Spectrograph on a Chip

Mass spectrograph on a chip, which integrates vacuum pumps, ionizer, an ion detector array, and control electronics onto a monolithic chip

architecture _{From DARPA}

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Conventional Applications Conventional Applications

Application of gyroscope -Inertial Navigation System -GPS

-Suspension operation of cars -Compensation of movement of

the hands for camcorder -Self-operation of robots Application of gyroscope -Inertial Navigation System -GPS

-Suspension operation of cars -Compensation of movement of

the hands for camcorder -Self-operation of robots

-Head Mounted Display(HMDS) -Night Vision Goggle(NVG) -Flight simulator

Gyroscope Applications Gyroscope Applications

1 10

Airbags

Anti-Collision Systems Active Suspension Anti-Skid Free Space Pointers

Vehicle

c) Home

0.01 0.1

Free Space Pointers Remote Control Devices Video Camera Navigation(GPS)

Toys and Sports Equipment(Varies) Machine Control

Attitude Control of Flying Objects Automatic Guided Vehicles Stabilized Platforms Robotics

Angular Vibration measurement(Varies) Monitoring of Body Movement Vibration Diagnotics

Industry Medical

Resolution (deg/sec

0.001

1 10 100 1000

Vibration Diagnotics Control for Paralysed Patients Surgical Instrument Wheel Chairs

Range (deg/sec)

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State of Art State of Art

Commercial product 1. SiVSG

1 10

c)

2. JPL/UCLA 3. Systron donner 4. Bosch product 2. JPL/UCLA 3. Systron donner 4. Bosch product

The others University The others University

0.01 0.1 1

1 1 2 2 3

3

Resolution (deg/sec

4 4 SNU High resolution SNU

& large range High resolution

& large range

y y

0.001

1 10 100 1000

Maximum measure range (deg/sec)

Microgyroscope Structure Microgyroscope Structure

Inner gimbal Inner gimbal

Driven mode flexure Driven mode flexure

Fixed anchor Fixed anchor

Sensed mode flexure Sensed mode flexure

Sensed electrode(+) Sensed electrode(+) Outer gimbal

Outer gimbal

Rebalancing electrode Rebalancing electrode

Sensed electrode(-) Sensed electrode(-)

Balancing electrode Balancing electrode Rebalancing electrode

Rebalancing electrode

Comb drive Comb drive

Schematics of in-plane vibratory gimbaled microgyroscope

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Structure of Micro Gyroscope Structure of Micro Gyroscope

Fixed anchor Driven mode flexure

Sensed electrode(+) Inner gimbal

Sensed mode flexure Vibrating gyroscope:

Sensed mode Sensed electrode(-)

Tuning electrode

Coriolis accelleration

Capacitive driving and sensing Stability: 4 degrees per hour

Driven mode Angular rate Outer gimbal

Comb drive

Rebalancing electrode

Principle & Fabrication Principle & Fabrication

x y z

Driving mode(2.036㎑) Sensing mode(2.720㎑)

Angular rate (z-axis) Coriolis force

sensed electrodescomb drive

attitude correction & tuning

balancing

Fabricated microgyroscope Sensor die with needle’s eye CDIP packaged sensor chip

• Sensor area - 1mm x 1.1mm

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Micro Mirror Array Micro Mirror Array

Mirror plate

Torsional spring Mirror post

Scheme of Display Using Mirror Array Scheme of Display Using Mirror Array

screen in

screen in screen out screen in

screen in screen out

V on V off

V on

V off V on V off

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Micro Mirror Array Projector Micro Mirror Array Projector

from IEEE Spectrum

Fabricated Micro Mirrors Fabricated Micro Mirrors

From T.I. From T.I.

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What is adaptive optics ? What is adaptive optics ?

Wavefront Sensor

Image Camera

Control System Beam Splitter

Deformable Micro Mirror Incoming

Image

Spatial Light Modulator Array Spatial Light Modulator Array for Amplitude & Phase Modulation for Amplitude & Phase Modulation

Mirror plate(100×100 μm²) Torsional spring

for amplitude modulation Electrostatic actuation

4μm 6μm

Upper electrode Bottom electrode Double crab leg spring

for amplitude modulation

Support post

Piston plus tilt mode operations are available.

Specification

Ö Maximum vertical deflection length : 4 ㎛

Ö Maximum rotation angle :

Schematic view of designed micro SLM

Double crab leg spring

for phase modulation ±4.5°

Application: adaptive optics

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Fabrication Process & Results Fabrication Process & Results

Bottom electrode forming

Spring structure define

1^stpost hole for spring structure forming by RIE

Mi Al d iti (10000 Å)

SEM view of fabricated micro SLM array

Si Thick PR SiO₂ Al

Mirror Al deposition (10000 Å)

Sacrificial layer removal by RIE

SEM side view of fabricated micro SLM array

Amplitude SLM Amplitude SLM

Two dimensional optical scanner(Ming. C. Wu et. al)

St d d th l l ili ff d b MCNC

• Standard three-layer polysilicon process offered by MCNC

• Electrostatically driven micro mirror

• Torsion spring structure

• Large area (400 × 400 µm²), Large angle (±14º)

• Pull in voltage : 70V, Resonant freq.: 1.5kHz

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Amplitude SLM Amplitude SLM

Laser-beam positioning mirror(R. S. Muller et. al)

•Beam steering mirror for scanning or off-chip beam positioning.

• Driven by comb actuator

• Mirror size : (500 × 500 µm²)

• Up to 20 degrees of angular range of motion

• Resonant freq : 29 kHz

Resonant freq.: 29 kHz

Scanner for off-chip beam positioning

Micro

Micro--Optical Components Optical Components

from UCLA

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Micro

Micro--Optical Bench on a Chip Optical Bench on a Chip

from UCLA

from UCLA Free-space micro-optical disk pickup head consists of a prealigned semiconductor laser, a collimating lens, a beamsplitter, a focusing lens, a 45^oupward-reflecting mirror and a 45^odownward-reflecting mirror.

RF MEMS Products RF MEMS Products

• Low loss transmission line

• Variable capacitor and inductor

• RF filter

• VCO(Voltage-controlled oscillator)

• Phase shifter

• Movable antenna

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Advantage of RF MEMS Advantage of RF MEMS

• Improvement of the power efficiency

– Replace electrical circuits with electromechanical signal processing

• Simply integrated with transmission lines

– Replace discrete, off-chip components (switch, varactor, inductor) with micromachined elements

→Monolithic implementationsare possible.

• Reduction of the fabrication cost, size, and complexity

Overlay CPW LINE Overlay CPW LINE

Propagation region of EM wave Signal line

Ground line A

A A´

A´

Signal line

Schematic view of OCPW line

• EM wave propagation along the overlapped area between

overhanging signal line and ground plate

– Reduction of the substrate dielectric loss

Ground plate

Fabricated OCPW transmission line

dielectric loss

– Reduction of conductor loss by widening the center signal line – Wide distribution of the edge

current density

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Tunable Two

Tunable Two--pole Resonators Filter pole Resonators Filter -- Two Two--pole Resonators Filter pole Resonators Filter

Micromachined variable capacitor

P t 2 RF choke

P t 1 DC bias source

Micromachined variable capacitor

Half λ line • Using 2-pole resonators

• Frequency shift with micromachined variable

Port 2 Port 1

Topology of two-pole resonators filter

micromachined variable capacitors connected to half wavelength resonators

• 6.2% center frequency shift from 30.6 GHz to 28.7 GHz

Fabricated Filter Fabricated Filter

Cantilever beam Variable capacitors

200 ㎛ ⅹ200 ㎛ • Fabricated with 2 ㎛-thick electroplated gold structures on the glass (Corning #7740) substrate

• Fabricated with 2 ㎛-thick electroplated gold structures on the glass (Corning #7740) substrate

λ/4 stub

Port2 Dielectric layer

Air bridges W: 20 ㎛, L: 190 ㎛ substrate

• Overhanging structures suspended 6㎛

substrate

• Overhanging structures suspended 6㎛

DC bias line DC voltage pad

Port1 Air bridge

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ext. chemical process ext. chemical

process

Albert van den Berg, University of Twente

ext. chemical process

Evolution of LOC from Chemical Sensors Evolution of LOC from Chemical Sensors

chemical compound

sensor actuator microfluidics

sensor actuator microfluidics chemical process

sensor chemical compound

sensor actuator chemical compound

electronic control electronic control electronic

control

electronic control

a) sensor b) sensor/actuator c) microanalysis system d) microchemical system Process of integration of sensors, actuators, fluidics, and reactors into a microchemical system

Technologies Comprising LOC Technologies Comprising LOC

Microfluidics Microelectronics

Micro Chemical Processing Unit (micro Integrated CPU)

Detection

Microchemistry Microfabrication

Bioinformatics

Desktop Synthesizer and Screener

- David Sarnoff Research Center

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Gene Chip on Markets Gene Chip on Markets

400,000 probes/1.28 cm²

• Affymetrix gene chip kit

Gene diagnostic chip

Fluorescence scanning

• Nanogen chip

• CMS chip and scanner

Reagent A

hν

Absorption - 495 nm Emission - 520 nm Window for

fluorescence measurement

Micro ELISA Fluidic System Micro ELISA Fluidic System

Rinse Reagent B

FITC

Li k l (GAPS) Virus or Cell (for

detection) Ab*FITC (or enzyme)

Blocking agent Primary Ab(probe) Waste

1. ELISA chip loading

2. Washing & samples are injected

3. Ab*FITC is injected 4. Fluorescence detection

Glass substrate Linker layer(GAPS) Reactor ELISA chip loaded

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DNA Chip DNA Chip

DNA chip - DNA sequencing DNA -double helix strands

DNA sequencing - Micro fabrication

(Micro stamping or synthesis by photolithography)

- One chip assay Performance is improved Assay time and cost is

Assay time and cost is reduced

Easy manipulation

Assembly of Oligonucleotide Probes Using Assembly of Oligonucleotide Probes Using

Photolithography Photolithography

Ultra Violet light DNA monomer ;

A-X, T-X, G-X, C-X Protection group;

Mask₁ -X

T

-

^X

(a)

T

A T A T

C C

Mask₂

Process repeat

(d) (e) (f)

• 4 lithographies are required for a base

• 64 lithography process are required for 16 base; lots of mask!!!

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UV illuminator

A

Maskless Photolithography Using Maskless Photolithography Using

Micromirror Array Micromirror Array

Micromirror On state Micromirror

Off state Selective

lithography

A11 A12 A13

A21A22A23

A31A32A33

A

A’

Fabricated biochip

Micromirror array (Virtual mask)

biochip

• MEMS technologyis originated from semiconductor technology.

• Key components of information technology and biotechnologyare

Conclusions Conclusions

y p gy gy

fabricated using MEMS technology.

• It is expected that MEMS market grows annually 20 - 30 % from 1998 to 2003.

• MEMS products are applied to micro inertial sensors, display devices, information storage devices, MEMS-based RF devices and micro chemical testing system.