System Configuration and Fabrication Technology for Distributed MEMS

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System Configuration and Fabrication Technology for Distributed MEMS Hiroyuki Fujita Center for International Research on Micronano Mechatronics (CIRMM) IIS, The University of Tokyo

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IIS, The University of Tokyo 2006.5.30

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Institute of Industrial Science at Komaba Research Campus of University of Tokyo

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CIRMM structure Institute of Industrial Science, Univ. of Tokyo CIRMM CIRMM

CNRS LIMMS CNRS/IIS Joint Lab

CIRMM professor Laboratories (12)

Paris office Coordination of research network

NAMIS International Research Network

Research Agreements

CNRS, UPE, VTT, IMTEK, SNU, EPFL, KIMM, EPM, NTHU, UW, Tohoku U

BEANS Life-BENAS Center 3D-BEANS Center MicroMachine Center

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LIMMS human exchange About 90 French researchers and students have stayed in LIMMS for 2-3 years typically

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Historical viewpoint • 1992 : CNRS wanted to put emphasis on MEMS (J.J. Gagnepain, Eng. Dept) • Open a laboratory abroad to develop teams in France • 1994 : fit IIS interest (F Harashima) • 1995 : Opening of the LIMMS – Research agreement • 2001 : Move to Komaba Campus • 2004 : upgrade to a UMI* – LIMMS / CNRS - IIS (UMI 2820) • May 2005: 10 Years was celebrated in Paris • 2008 : LIMMS renewed until March 2012 * UMI: international joint unit

NAMIS Autumn School

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Lectures over a week Ph.D students and young researchers from NAMIS partners were invited to IIS. 37 of them attended a full week autumn school. 37 were invited from six countries Lectures by professors, poster presentation from students and two afternoon experimental sessions. experiments

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Research Environment LIMMS takes advantage of the up-to-date micro fabrication facilities of CIRMM / IIS (Center for International Research on Micro Mechatronics) Silicon-Process Cleanrooms •Photolithography, Low-Pressure Chemical Vapor Deposition, Ion-Implantation,and equipment for MOS processes

MEMS-process Cleanrooms •Deep RIE, Wafer Bonders, Electron-Beam Patterning

Semiconductor Characterization Cleanrooms •Probestations, Laser Doppler Vibrometer, SEM, Laser Microscopes

Bio-Engineering Cleanrooms •Chemical Draft Chambers for Bio-Processes, Cell Culture & Molecular biology Facilities

Nano scale measurement platform •TEM, FIB, STEM, Field-Emission SEM, Sub-atomic precision AFM equipment

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Content • • • •

MEMS trend toward parallel distributed system Cilia motion conveyer (open-loop type) Airflow conveyer with feedback control Fabrication technology for DMEMS – Self-assembly – Printing

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Examples of MEMS devices Denso

UC Berkeley

AD

IEMN/CNRS

U-Tokyo

Olympus

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Hetero-Functional Integration Technology Integrated System with Heterogeneous Functions

Process Integration Bio-chemo device

Bio chemo technology

Nano/quantum device

Nano tech.

Optical device

Compound semiconductor tech.

Electronics device

VLSI/CMOS technology

Mechanical device

MEMS

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Features of MEMS Miniaturization, Integration, Multiplicity Miniaturization micro manipulation tasks in narrow spaces Array device

Multiplicity

Parallel cooperative task

High-density packaging Micro electronics

Integration

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Example of arrayed MEMS: “DMD projector” DMD=Digital Micromirror Device Screen

Ramp

Image

Lens

Image signal

Many movable micromirrrors are driven independently

Black absorber 13

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Example of arrayed MEMS: “DMD projector” DMD=Digital Micromirror Device

Micro system --> Micromirror

Screen Batch process --> Array device

Lens C-MOS integration --> Control circuit 16mm

Image signal

- Open loop control

Many movable micromirrrors are driven independently

14

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From display to intelligent surface • DMD drives its actuators according to given data and shows images represented by the data. • If the device is equipped with sensors, can perceive its surrounding condition, and drives its actuators to perform external work for modifying the condition, this provides you an intelligent surface. • Some examples of the intelligent surface include a smart skin to control the vortex over a airplane wing, and a smart conveyer on which parts are transported, positioned and aligned.

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Smart skin (intelligent surface) Taking best advantages of MEMS features Miniaturization , Integration of Microelectronics , Multiplicity Adaptative Wing

Sensors + Local data processing + Actuators

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System configuration of intelligent surface • In the case of a smart skin, two key issues are the local detection of initial vortex over a large area and the fast response to eliminate it. • This cannot be achieved by conventional centralized control because of two reasons: (1) too many wirings to all the sensors and actuators, and (2) processing and communication delay. • Autonomous decentralized system (ADS) is a promising concept for such a system configuration. • In the ADS, many autonomous cells having sensors, local processor and actuators cooperate each other via communication between them.

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MEMS Conveyance System for Pneumatic Two-Dimensional Manipulation based on Autonomous Distributed Systems Y.Fukuta, Y.Mita*, Y-A. Chapuis, M.Arai and H.Fujita Institute of Industrial Science, The University of TOKYO *Dept. Electric Engineering, The University of TOKYO

19

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Previous research: Control of array device • Macro device – Flexible Transfer System (T.Fukuda et al. 1999) – Magic carpet (Oyobe et al. 2000) – …

• Micro device – Fault tolerant control (Konishi et al. 1994) – Programmable Force Field (Boehringer et al. 2000) – …

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Our research project Airflow force= Contact-free type

MEMS actuator Array Distributed sensing & processing

Cooperation tasks of Array Device

Advantages : ~ Local communication ~ - Quick response to the object motion --> Easy control of objects - Save electric wiring

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“Distributed Sensor & Processor” Developed with C-MOS LSI tech. by our group One cell:

Currently, ~ 1 x 1 mm Emulation in PC 2

Optical sensor (photo diode) Distributed processor

Y.Mita et al., Trans. IEICE C-2 vol.82 pp108, 1999

I’m at edge!

(1) Image by optical sensors

(2) Communicates with next cells

(3) According to the communication result, 22 next step

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Concept of our MEMS device object

Air-Valve CLOSED

Cross-sectional view

object

Through hole for air-flow Movable nozzle

Suspensions Electrostatic force Off

Air flow

Off 23

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Fluidic FEM simulation of a closed valve object Vertical force


object

leak

gap

FEM Valve simulation Off

Air flow

Off

Air-Valve CLOSED 24

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Air-Valve CLOSED


object

Off

Air flow

ON 25

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Air-Valve CLOSED

Air-Valve OPEN


object

Off

Air flow

ON 26

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Concept of our MEMS device

Air-Valve OPEN Cross-sectional view

object object Air flow

Off

Air flow

ON 27

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Concept of our MEMS device

Air-Valve OPEN Cross-sectional view

object Air flow

Off

Air flow

ON 28

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Fluidic FEM simulation of an open valve Vertical force Lateral force


Air flow

FEM simulation Off

Air flow

ON

Air-Valve OPEN 29

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Schematic & SEM view of one cell Front

200 mm Electrostatic force

Back

1mm

200mm

30

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Orthogonal pattern of basic cells Front

Back

1mm

560 actuators were obtained with no lack! Back

1mm 31

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Control system for Open-Loop

Conveyor surface

Control program

object

Actuator driver 128 wires

Air source 32

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Result of the open-loop control Toward the force equilibrium point ~ All actuators toward the center ~

35mm

air-flow

Si chip 3x3mm22 mg

air-flow 35mm 33

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Control system for Closed-Loop Video camera

Feedback loop

Control program based on distributed processing Actuator driver

Conveyor surface object

128 wires

Air source34

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Schematics of closed-loop control ~Edge detection & Step motions~ 1. Edge detection 2. Actuators ON 3. One step motion

How do we detect the edge? Distributed Go Right! processing!

(1) Image from video camera is mapped into matrix image

(2) A cell communicates with next cells (3) Detect edge (4) Drive actuators

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Result of the closed-loop control

35mm

~Edge detection & Step motions~

Plastic chip approx. 5×5×1 mm3 38mg

35mm 36

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Summary of this work MEMS actuator Array Distributed sensing & processing Cooperation tasks of array device

Image sensor & Processor array

Advantageous - Quick response to the object motion - Number of electric wiring is much less than that We emulate the task into a PC of centralized systems

ADS

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Conclusions • MEMS array realized the air-flow conveyor for micro manipulations. – The MEMS actuator array controlled the direction of air-flow as designed.

• Distributed controls were developed. – Open-loop control: Conveyance for the force equilibrium point was realized. – Closed-loop control: Conveyance by pushing the object’s edge was realized.

• Integration with the control chip is under investigation. – C-MOS based control chip was already developed. – Autonomous Distributed Systems (ADS) is the final goal of our project. 38

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Acknowledgements • We would like to thank Prof.Konishi and the member of Konishi lab. in Ritsumeikan Univ. for a lot of discussion. • The C-MOS LSI chip was designed at IEMN-ISEN/France with Prof.Kaiser and Dr.Stefanelli. • This research is partially supported by the 21st Century COE program in Electrical Engineering and Electronics for the Active and Creative World, The University of Tokyo.

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Previous research on arrayed MEMS conveyer • Contact type – Ciliary actuator array (Ataka et al. 1993, Suh, et al. 1997)

– Magnetic coil array (Inoue, et al. 1996, Nakazawa, et al. 1999, Komori, et al. 2000)

(Ataka et al.)

– Magnetic actuator array (Chang Liu et al. 1995) – Electrostatic actuator array (Suh, et al. 1999) – -- Fragile for objects collisions

• Contact-free type – Airflow (Pister et al. 1990, Konishi et al. 1994, Guenat et al. 1998)

– -- Difficult to control floating objects

(Konishi et al.) 41

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Biomimetic Transport with MEMS Cilia Similar to “crowd surfing”

[Ataka et al. Transducers’93]

Many small actuators operating together to perform larger tasks © Karl F. Böhringer

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Improved Polyimide Ciliary Arrays

SEM picture: J. Suh

• • • •

Single cilium cross section Thermal bimorph design Picture by J. Suh 30µm actuator deflection 8  8 grid of “motion pixels” on chip [IEEE CS&E’97, IJRR’99] © Karl F. Böhringer

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Biomimetic Transport with MEMS Cilia A programmable surface for • Linear motion • Centering and continuous rotation • Centering and aligning Cilia array implements “squeeze fields” open-loop control squeeze force

Open-loop orientation [IEEE MEMS’97, Suh et al. JMEMS’99] © Karl F. Böhringer

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Biomimetic “Walking Chip” – Two cilia chips mounted upside down on miniature pc board – Mass 500 mg, size 30  10  1 mm – 512 “legs” bottom view

© Karl F. Böhringer

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Walking Chip Demo Side view: one motion pixel is visible

• •

Full 3 DOF motion Speeds up to 0.6mm/sec

•

[Mohebbi et al. ASME’01] [Chen et al. Hilton Head’06] [Erdem et al. JMEMS’10]

• •

1mm © Karl F. Böhringer

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Fabrication issues of DMEMS • Sensors and actuators are densely arrayed on the surface over circuits. Monolithic layered integration or stack hybrid integration are used. • Areas over a few square meters cannot be covered by wafers on which conventional micromachining is conducted. New fabrication methods are required; those must be inexpensive and scalable. – Self assembly of many parts over a large area. – Printing technology for MEMS fabrication.

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Self assembly of parts • Self-assembly is the way living creatures build their body. We can learn from the nature. • Hydrophobic patterns on a hydrophilic surface can attract parts with a hydrophobic side in water. • Patterns of magnetic materials can attract magnetic parts under magnetic field. • Mechanical patterns of a specific shape can capture matching parts under vibration agitation.

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Templated Self-assembly

June 2010


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Templated Self-assembly


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Real-time Tracking of Self-assembly aperture sites: 200; % excess parts: 50%; agitation frequency: 525Hz


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Fabrication of Large-Area MEMS

Overall device size

10m

Large-Area MEMS

Roll-to-Roll printing

・printing ・molding ・stamping *1

1m

*2

MEMS ・photolithography ・etching ・thin film deposition 1mm 1nm

1mm

1mm

Flexible display

Minimum feature size *1 : Mäkelä, Tapio; Jussila, Salme; Vilkman,M.; Kosonen, Harri; Korhonen, R. “Roll-to-roll method for producing polyaniline patterns on paper”, Synthetic Metals. Vol. 135-136 (2003), 41-42 *2 : http://www.vtt.fi/

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Prospect of large area flexible MEMS Yuhsuki Taii, Chengyao Lo, Hiroshi Toshiyoshi MEMS flexible display, MEMS wall paper ???

Fabry-Perot interferometer type flexible color display

Roll-to-Roll printing

Oversized flexible display sheet

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F/P configuration for color pixel 40

20

400

600 波長 [nm]

800

20

0

Simulation

100

10

10 0

ON (Green)

30

400

600 波長 [nm]

800

transmission (%)

OFF (gray)

30

透過率 [%]

透過率 [%]

40

80

T Blue

60 T=240nm Green T=310nm

40

Red T=370nm

20 0

400

500

600

WL (nm) White back light

700

800

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Device confgration Flexible film (PEN,16um)

Total thickness < 220μm

Electrode/mirror (Aluminum,12nm)

→ spacer (resist,600nm)

F/P thin film (SiO2,310nm)

Electrode/mirror (Aluminum,12nm)

Flexible substrate (PEN,200um)

0.2-0.6 mm

flexible!

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Pixel at different voltage Membrane motion

Experimental set-up CCD

0V Glass substrate

20V

90V lamp

Pixel image

300um

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Pixel size 200um

400um

400um

2006.5.30 400um

RGB pixels 400um

600um

800um

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R2R Process for Large Area Display (Final Goal) Top Film Aluminum

Lamination

Lift-Off Flexo

Reverse Gravure

Aluminum

SiO2

Bottom Film Lift-Off

Spacer Gravure

20cm

VTT TECHNICAL RESEARCH CENTRE OF FINLAND

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Room with Ambient Intelligence DMESM wall paper and carpets Room environment is kept comfortable by arrayed MEMS sensors and actuators. Optical sensor＋LED Microphone＋speaker Temp. sensor＋heater Humidity sensor＋ventilator Human sensor on wall paper & carpet

Active MEMS carpet for cleaning

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Conclusion • Silicon-based MEMS in micrometer scale has matured. Such MEMS enters the phase for commercialization. • One of the future prospects is the distribute MEMS for display and smart skin, etc. • Integration of MEMS sensors, actuators and electronic circuits can provide a convenient platform for distributed MEMS with closed-loop control. • As the distributed MEMS tends to occupy large-area, new fabrication technologies are needed such as printing and self-assembly.

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Acknowledgment • • • • •

MEXT JSPS Global COE Program JST CNRS (France)

• METI • NEDO • MMC