memsの新しい話題 - mems パークコンソーシア …mems の新しい話題田中秀治...

MEMSの新しい話題

田中秀治工学研究科ロボティクス専攻

マイクロシステム融合研究開発センター東北大学

S. Tanaka Lab’s Propriety

In cooperation with

1mems tohoku

今年の話題

2

第1話マイクロミラーデバイスは死んでいない

第2話いよいよMEMSアクチュエータが実用化？オートフォーカスデバイスとMEMSスピーカ

第3話超音波指紋センサは次の大量生産MEMSの第一候補

第4話中国のMEMSは？

第5話絶好調のBAWフィルタに強敵：新しいSAWデバイス

第6話 AI時代のバスネットワーク型触覚センサ

今年の話題

3







Actuation Types of Micromirror Device

4

1. Electromagnetic① Moving coil② Moving magnet

2. PiezoelectricMany companies are developingthis type (not yet very successful).

3. Electrostatic

Lemoptix, EE Times (2014.9.16)HD level

スタンレー電気,応用物理学会2014春17p-E9-7共振軸±14°非共振軸±8°（60 V）

Microvision, J. MEMS, 15 (2006) 786SVGA level (1st generation)

OPUS MicrosystemsSVGA level

MEMS光スキャナを用いた世界初のHUD（ﾊﾟｲｵﾆｱ）

5

棚橋祥夫他,レーザープロジェクターを用いたフルカラーヘッドアップディスプレイの開発,PIONEER R&D, Vol. 22 (2013)

Microvisionの第一世代光スキャナを利用780×260 pixel 画質が悪く，期待を裏切る。

J. MEMS, 15 (2006) 786製品は異なる構造

2012年7月発売，3000台出荷？

Laser Projector Using Micromirror Device

6 Photograph: Sony website

LaserRed×2, Green×2, Blue×1206 mW，32 lm

150×77×13 mm3

272 g, ~350 US$

Photograph: Sharp websiteSony PicoprojectorSharp “RoBoHoN”

Microvision, 2nd gen micromirror device1980×720 pixels, 5.5×13.4×9 mm3

Chipworks

Mirror:1.2 mm×1.1 mm

Sharp “RoBoHoN” with Microvision’smicromirror device (1280×720 pixels)

MEMS光スキャナの課題

7

１）アクチュエータの発生力

特に非共振軸で問題：発生力不足のため，非共振軸のばね定数を下げると，あるいはアクチュエータを大きくすると，共振周波数が下がり，60 Hzリニアスキャン時に不要振動が発生。

駆動力について，現状，電磁駆動が最も強力。圧電駆動，静電駆動と続く。

大きなミラー → 小さなスポットサイズ D ～Φ1.5 mm大きなスキャン角 → 分解能向上（スポットサイズ一定で） θOPT > 50°高い共振周波数：共振軸 f >20 kHz，非共振軸 f >0.5~1kHz

２）ミラーの平坦性大きなミラーを高速に動かしても，ダイナミックにたわまないミラー→ 動たわみ低減構造を付けると，マスが増えて，駆動が難しくなる。

同時に実現は困難

３）トーションばねの強度トーションばねに大きな歪が加わる。数百MPa～1 GPa未満で設計。HD画像（1280×720）までなら問題ない。

それ以上では，どちらかと言うと，アクチュエータが問題だが，強力な電磁アクチュエータを利用すると，トーションばねの破断が問題になるところまでねじれる。

共振軸

非共振軸

光スキャナの性能比較

U. Baran, … H. Urey (Koç Univ., Microvision, Polytechnic of Turin, EPFL), MEMS 2012, pp. 636-639

Microvision（第一世代）

θOPT∙D∙f

1軸圧電MEMS2012

LG Electronics，2軸電磁（参考）ECO SCAN（日本信号）電磁2軸ESS211-1.5 kHz/440 HzθOPT∙D∙f = 360電磁1軸ESS122-8kHzθOPT∙D∙f = 580

640×480800×600

1280×1024

1920×1080

Fraunhofer ISIT，2軸圧電

8

Microvision（第二世代）

某社開発品（推定）

Microvision 第二世代

Microvision 第一世代

Other Applications of Micromirror Device

9

Intel RealSense(ST MEMS scanner is used.)

GlimmerglassNetwork switch using micromirrors

Robert Bosch Scanning laser headlight

STMicroelectronics720p micromirror

Lemoptix (France) acquired by Intel

Lenovo ThinkPad Yoga 15 (2015)

Intel RealSense Using ST’s Micromirror

10

LenovoThinkPadYoga 15

Chipworks (2015)

Structured IR light probably througha patterned screen

STMicroelectronics

The line lens generates horizontally stretched light from circular IR laser.

1 axis MEMS mirror

Eye Tracking (AdHawk) and Intel AR Glasses

11

N. Sarkar et al. (Univ. Waterloo, Canada), Transducers 2015,pp. 855-888

AdHawk (Canada) Intel

Electrothermal micromirror65º×25º (optical), 3.3 V, <15 mA, 750×750 μm2

AR glasses

Omnidirectional Scanning LIDER

12

U. Hofmann et al. (Fraunhofer ISIT) Optical MEMS 2012, 2013

Φ7 mm mirrorElectrostatic actuation±15º tilting angle at 550 Hz resonation in vacuum

Murata Electronics and VTT (Finland)

AlN and ScAlN

High Speed Position Tracking by MicromirrorMirrorcle Technologies, Inc. （Adriatic Research Institute’s spinout）

13

Laser

MicromirrorPD

Retroreflector

Up to 100 m

今年の話題

14







Varifocal Liquid Lens with PZT Actuator

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Stephane Nicolas et al. (CEA Leti, Wavelens), IEEE MEMS 2015, pp. 65-68

PZT actuator Polymer membrane(several μm) Silicon (back-ground to 100 μm)

Glass (polymer bonded)Optical oilThick photoresist

An accurate volume of optical oil is automatically dispensed into cavities, and then the glass wafer is bonded.

DRIE and oxide wet etchOptical oil dispensing andpolymer bonding

PZT actuator and transparent polymer

4.5×4.5×0.4 mm3Aperture 2.2 mm

Varifocal Liquid Lens with PZT Actuator

16

Stephane Nicolas et al. (CEA Leti, Wavelens), IEEE MEMS 2015, pp. 65-68

Optical power variation vs. driving voltage Wave front error (20~ 40 nm)

Step response of optical power Life time (Optical power error vs. cycles)

Aperture ~ 2 mm?

±0.5 diopters

Varifocal Gel Lens with PZT Actuator

17

Mahmoud A. Frghaly et al. (University College of Southeast Norway, PoLight), Optical Express, 24, 25 (2016) 28889

Calculated performance(Focal length f and RMS wavefront error versus applied voltage)for optimum geometry of varifocal lens

Schematic structure of varifocal lensPZT thickness = 2 μmGlass thickness = 20 μmDiameter = 3 mmAperture = 1.6~1.7 mm

Circular

Circular

Rectangular

Rectangular

Reliability of PZT Thin Film

Fuji Film Dimatix, PiezoMEMS 2013

18

• Smoother surface is better in terms of breakdown.• The doping of Nb and Mn improves breakdown voltage.• The bottom electrode of conductive oxide (e.g. SRO) is necessary for

better reliability. Pt works as a catalyst for hydrogen-induced degradation of PZT.

• Dry etching can damage PZT, resulting in lower breakdown voltage.• PECVD also can damage PZT by hydrogenated compounds.

“Conventional” MEMS SpeakersSang-Soo Je et al. (Arizona State University), IEEE Trans. Biomed. Circut. Syst. 3, 5 (2009), pp. 348-358

19

NdFeB magnet20 mm outer diameter4 mm inner diameter0.5 mm thickness

For hearing aids(Small SPL is OK.)

20 mA rms drive0.13 mW averagepower0.8 μm amplitude→ 106 dB SPL

(at proximation?)

Height reduction of dynamic speaker by MEMS technology

↓Some height reduction is possible, but drastic miniaturization is difficult.Low power?Low cost?

Fundamental Discussion on MEMS Speaker

20

Sound pressure

Volumetric speed

SPL

r Distance from sound sourceρa Density or aira Radius of diaphragm (a<<r)A Amplitude of diaphragm

(piston mode)ω Angular frequencyV0 Vibration velocity

(dB)

SPL is proportional to volumetric speed.→ Down-sizing basically results in small SPL.

To make SPL constant , ω2A must be constant.→ Larger amplitude A is necessary at lower

frequency. (A is inversely proportional to the square o frequency.)

→ MEMS actuators are difficult to apply.

a rAsinωt

Displacement larger than several hundreds μm→ Magnetic actuation is suitable.

But, there is a little merit of MEMS compared with dynamic speakers.→ Resonant actuation, but a penalty of frequency characteristic

(Point source)

Recent Development of MEMS Speakers

21

Usound (Austria), FhG ISITPiezoelectric MEMS speakerPZT film5×7×2 mm3

2~15 kHzProduction in STMicroelectronics (planned)

Audio Pixels (Australia)MEMS digital speaker arrayDigital sound reconstruction (no DAC)Production in Tower Jazz (planned)Collaboration with Sony Kagoshima around 2015

Replacement of miniature dynamic speakersSpeakers for earphones and hearing aidsApplications for noise cancelling, speaker arrays etc.

Digital Sound Reconstruction

22

Brett M. Diamond et al. (Carnegie Mellon Univ.), IEEE MEMS 2002, Transducers 2003

Audio Pixels (2015)

The resonance frequency of the diaphragm is only ten-odd kHz. The samplingfrequency of the speaker is only 8 kHz.The resonance of the diaphragm and pulsed drive at the sampling frequency causesdistortion (unwanted spectra), which must be filtered out.Anti-phase sound pressures generated pull-in and pull-out cancel together.

In 2003, CMU reported an 8 bit digitalspeaker with 255 array of 216 μm squarediaphragms driven electrostatically.About 80 dB SPL was demonstrated.

Bi-directional actuation

Piezoelectric MEMS Speaker (FhG ISIT)F. Stoppel et al. (Fraunhofer ISIT), Transducers 2017, T3P.098, pp. 2047-2050

23

• A cantilever structure produces larger displacement than a closed diaphragm.

• Gaps between the cantilevers are just 5 μm, avoiding air leakage.

• The tweeter structure inside is lifted by the woofer actuators, working as a woofer membrane.

• The tweeter actuators vibrate independently from the woofer actuators to generate high note.

10 mm square

Piezoelectric MEMS Speaker (FhG ISIT)F. Stoppel et al. (Fraunhofer ISIT), Transducers 2017, T3P.098, pp. 2047-2050

24

FhG ISIT MEMS speaker(10×10 mm2)

Commercial dynamic speaker(AAC DMSP0916S, 9×16×3 mm3)

Designed

The device is fabricated by standard PZT MEMS process.

• The woofer and tweeter have resonance characteristics, covering different tones, to obtain large SPL (i.e. displacement).

• The frequency characteristic is not flat, but the frequency characteristic of the drive amplifier (ASIC) is tuned accordingly.

Piezoelectric MEMS Speaker (FhG ISIT, IDMT)F. Stoppel et al. (Fraunhofer ISIT, Fraunhofer IDMT), IEEE MEMS 2018, pp. 1068-1071

25

2 μm PZT / 15 μm poly Si membrane9 μm gap (5 μm in design)Sputtered PZT: e31,f = 23 C/m2

4×4 mm2

60 μm difflection at 20 V drive

Flat frequency characteristics is obtained with an equalizerSPL (2 V drive) higher than 85 dB(A) limit for the equivalent continuous sound level when using headphones defined in EN 63268-17% harmonic distortion at resonance (8.3 kHz) by subharmonic stimuli

今年の話題

26







Fast Grown Fingerprint Sensor Market

27

2016 Revenue of MEMS and sensors companies (including fingerprint sensor)

Fingerprint Cards (Sweden), Synaptics (San Jose) and Goodix (Shenzhen) have grown rapidly. They are supplying capacitive fingerprint sensors.The growth of their revenue may slow down or become negative in 2017.

IHS Markit (2017)

Fingerprint Biometrics

National Institute of InformaticsProf. Isao Echizen (Source: Reuters)

28

Fake fingerprint

Fingerprint can be recognized by high-end digital camera

Fingerprint Biometrics Using 3 Level Features

29

Anil K. Jain et al., IEEE Trans. Pattern Analysis Machine Intelligence, 29, 1 (2007) pp. 15-26from Prof. D. Horsley’s Seminar, 27 April 2017, Tohoku University(Slides are available at S. Tanaka Lab website)

TFT-based Ultrasonic Fingerprint Sensor

30

J. K. Schneider (Qualcomm), Biometrics Within the Wireless and Mobile Computing Industry, 2013 from Prof. D. Horsley’s seminar, 27 April 2017, Tohoku University(Slides are available at S. Tanaka Lab website)

• PVDF piezoelectric ultrasonic fingerprint sensor

• TFT-based manufacturing• 500 dpi• Scalable to virtually any size• Single-finger, four finger and

full hand sensor

Ultrasonic transducer

TFT-based Ultrasonic Fingerprint Sensor

Glass

Thermo-decomposed polymer? (<100 nm)

AlN

Polymer (e.g. SU-8)

Displace or aluminum case on it through matching layer

Mo

US20150165479A1

Die size:ten-odd mm×several mm

Vivo XPlay 7

VivoXPlay 7(2017)The ultrasonic fingerprint sensor under OLED wasused.

31

Integrated Ultrasonic Fingerprint Sensor

32

Prof. D. A. Horsley (UC Davis), Prof. B. E. Boser (UD Berkeley), InvenSense, Inc.AlN film

Pixel size 43×58 μm2

56×110 pixels582×431 dpi

Prof. D. Horsley’s Seminar, 27 April 2017, Tohoku Univ.(Slides are available at S. Tanaka Lab website)

FBI standard resolution of >500 dpiImaging dermalstructureRobustness to contamination and moisture

今年の話題

33







MEMS Company Ranking 2017

34

Million US$

http://www.yole.fr/iso_album/illus_status_mems_industry_top_mems_ranking_yole_may2018.jpg

【マイクロフォンメーカ】Knowles（首位）STMicroelectronicsInfineon（GoertekとAACにダイ供給）TDK（旧EPCOS，旧InvenSense）GoertekAACオムロン（AACにダイ供給）

QST’s MEMS-LSI Integration Process

35

• Similar to InvenSense’s process• Dr. Kegang Huang (Vice President, QST)

was in InvenSense, Fairchild Semiconductor etc., working for the construction of MEMS production technology.

• The process has been installed in ShanghaiHua Hong NEC Electronics factory of HuaHong Semiconductor Group (華虹半導体).

K. Wang (QST), Int. Conf. Commercialization Transducers & MEMS 2017, 田中秀治, 欧米MEMS企業の牙城崩せ、中国勢が続々切り込む：日経テクノロジーオンライン171031

TDK-InvenSense’s MEMS-LSI Integration Process

Steven Nasiri and Martin Lim, InvenSense, Inc.

Ge (700 nm)

Al (500 nm)

Direct bonding

30 μm

Al-Ge eutectic bonding450 ºC, 300 N/wafer,4 % H2 in N2

x y

CMOS

36

~70 μm

MiraMEMS (TSMC Above-CMOS MEMS)

37

Monocrystalline Si (a few μm) Gap (a few μm)

CMOS wafer

BEOL Last CMOS metal

A monocrystalline Si layer is bonded with a polished CMOS wafer, and used for MEMS.

Figure from IMEC(Poly-SiGe was gaven up)

Miradia → MiraMEMS (Suzhou Good-Ark Electronics: 蘇州固鍀電)

Monocrystalline Si Micromirror Array (Fh.G IPMS)

Process of monocrystalline Si micromirror array on CMOSStep 2: Direct bonding at 400 ºC or spin-on glass bonding at 300 ºC

T. Bakke (Fraunhofer IPMS), 2005 SUSS MicroTec Seminar in Japan, 6 Oct. 2005

38

Micromirror Array for Maskless Lithography

Optical maskless lithography （Micronic Laser Systems）

Resolution smaller than 200 nm

A few thousands of 256×256 images per second

KrF excimer laser(λ = 248 nm)

39

今年の話題

40







Requirements for Acoustic Wave Filters

41

• Lager power handling ← LTE (Overlap of subcarrier)• Smaller nonlinearity (Inter Modulation Distortion) ← Carrier aggregation• Improvement of basic performance (IL, cut-off characteristic and TCF)

← Difficult-to-deal bands (e.g. LTE Band 25 and Band 11+21)• Higher frequency for 5G (3.5~5 GHz)

Band 25 (Left) Transmission, (Right) ReflectionT. Takai et al. (Murata Mfg.), IEEE IMS 2016

Up link: 1850 MHz〜1915 MHz (BW 65 MHz)Down link: 1930 MHz〜1995 MHz (BW 65 MHz)Guard band: 15 MHz → Extremely narrow

5th Generation of Wireless Communication

42

3GPP 5G NR Phase 1NR bands below 6 GHz- Band n77 3.3~4.2 GHz- Band n78 3.3~3.8 GHz- Band n79 4.4~5.0 GHz

Balazs Bertenyi (Nokia),Chairman of 3GPP RAN

Low band Mid band1 GHz 3 GHz 4 GHz 5 GHz

600/700 MHz 3.3~4.2 MHz 4.4~5.0 GHz

RF無線フロントエンドモジュール内の

周波数選択用SAW/BAWフィルタ

SAW or BAW?

Andreas Link, Phil Warder (TriQuint Semiconductor), “Golden Age for Filter Design,”IEEE Microwave Magazine, August 2015, pp. 60-72

430.5 GHz 1.5 GHz 2.5 GHz

Hetero Acoustic Layer SAW

Acoustic Waves

44

Bulk waves

Longitudinal wave

Fast shear wave

Slow shear wave

Surface waves

LLSAW

LSAW

Rayleigh wave

Phas

e ve

loci

ty

High frequency and high k2,but leakyAcoustic energy can be confined by HAL structure.

HAL (Hetero Acoustic Layer) types of SAW device

Thinned single crystal LN or LT (t < λ)

Energy confinement structure

Bulk wave

LSAW/LLSAW

High Performance SAW Device Using Thin LT

45

T. Takai et al. (Murata Mfg.), IEEE IUS 2016岩本英樹他 (村田製作所), 日本学術振興会第150委員会, 第148回研究会, 2017.5.16

Si

LiTaO3 h ≤ λ (LSAW is confined.)

λ

Energy confinementTCF improvement

HAL SAW device

Standard SAW device(42ºY-LT)

>80 dB

50ºYX-LT for reported device

High thermal conductivity

Incredibly high performance in both Q factor and TCF

Bode Q ~ 4000Bandwidth 3~3.5%TCF of Band 25 duplexer+8 ppm/K at left edge−8 ppm/K at right edge

I.H.P. SAW® technology by Murata Mfg.

Bandwidth

High Performance SAW Filter Using Thin LT

46

Tsutomu Takai et al. (Murata Mfg.), IEEE International Ultrasonics Symposium 2016

Bandpass characteristic of“difficult-to-deal” band 25 duplexer

Band 25 duplexer(2×1.6×0.6 mm3)

Temperature characteristic of“difficult-to-deal” band 25 duplexer

TCFLeft edge +8 ppm/KRight edge -8 ppm/K(About 1/5 of 42ºYX-LT SAW)

Hetero Acoustic Layer SAW Using Thin LN

47

M. Kadota, S. Tanaka (Tohoku University), IEEE International Ultrasonics Symposium 2016

Au IDT, 0.21 μm

AlN, 0.42 μmSiO2, 0.35 μm

Glass


Impedance ratio = 83 dBBandwidth = 21.3%

Excellent performance ever reported


LiNbO3

Measured

83 dB

Y-cut LN, 3.6 μm 21.3%

Thin LT/Quartz Hetero Acoustic Layer SAW

48

M. Kadota, S. Tanaka (Tohoku University), IEEE International Ultrasonics Symposium 2017

400 500 600

BW 5.0%Z ratio 82 dBλ 7.76 µm

Cu/42oYX-LT

Impe

danc

e [Ω

] Cu/20oYX-LT/40oY90oXquartz

800 900 10001

10

100

1000

10000

100000

Frequency [MHz]

BW 4.2%Z ratio 51 dBλ 3.78 µm

C

51 dB

82 dB(Bode Q 3000)

40ºY90ºX quartz

20ºYX LT (1.12 μm)

• Quartz shows positive TCF of LSAW, depending of crystal orientation.

• 90º propagation of rotated Y quartz has fair coupling of LSAW.

今年の話題

49







Robots for Menial and Hard Work

51

R NAVI, Japan Robot Association

The plastic cover is picked up. The cover is set on the lunch box (side dish).

The covered lunch box is set another lunch box (rice).

The production of boxed lunch is a menial but hard work. Working room is at 15ºC.

By introducing robots, the number of workers was reduced from 30 to 22.The employees moved to more creative works and have become happier.

This is a very simple work, but more works can be done by robots in the age of AI.

Robots Working with Human

52

YuMi (ABB) receives parts from the lady and assemble them partially.The final screwing and checking are done by the lady.

College Cafe by Nikkei (http://college.nikkei.co.jp/article/88001017.html)

Can we install different sensors in thesame manner on a common bus network?We need to install a lot of sensors, but alsoexpect fast response. Is it possible?Can we configure each sensor separately?→ Sensor platform LSI

Can we smartly install many sensors in robots?

Relay node

Analog senor

Digital sensor 1（I2C or SPI）

Digital sensor 2(Clock different from 1)(I2C or SPI)

AMP, ADC Noise

53

Kludge

Low density Busy wires Inconsistent

interface Low performance

especially for analog sensors

Sensors Connected to Bus via Platform LSI

54

Conventionalmethod

Platform LSI Sensor platform LSIChip-size multi-axis sensor integrated with platform LSI

Bus

Relay node

Analog senor

Digital sensor 1（I2C or SPI）

Digital sensor 2(Clock different from 1)(I2C or SPI)

AMP, ADC Noise

Low density Busy wires Inconsistent

interface Low performance

especially for analog sensors

High density Minimum wires Consistent

interface High performance Event driven

Relay node

Demonstration of Event-Driven Operation

Please watch the student’s finger(s) and the oscilloscope.Only when the sensor is pushed, a packet appears on the oscilloscope.55

16 touch sensorson the bus

Tactile Sensor Network Covers Robot Surface

56

Integrated sensor

Integrated Finger Sensor (3 Axis Force + Temp)

57

CMOS

CMOS

LTCC

Diaphragm

Sensing boss

ZX

Y

Bonding pad

Au sealing ring Capacitive

electrodeStopperAu bump

Sho Asano et al., IEEE MEMS 2016, pp. 850-853, Sensor Symposium 2016

Demonstration of Finger Sensor on Robot

58

HotCold Hot or cold water

今年の話題

59







マイクロデバイスの研究開発，お手伝いします。

60

研究室クリーンルーム

マイクロ・ナノセンター（MNC）

マイクロシステム融合研究開発センター

小片ウェハ

4インチウェハ

6インチウェハ

田中(秀)研究室が一貫してお世話

基礎研究から製品開発まで小片ウェハから6インチウェハまで

企業単独での開発より短時間・低コストで成果が得られるように支援します。本学で試作したデバイスの商用利用も可能です。

MEMSに関するコンサルティングも行っています。企業からのオーダーに応じてプライベートセミナーを開催します。

Assoc. Prof.Takashiro Tsukamoto

Michio KadotaAssoc. Prof.Masanori Muroyama

Assoc. Prof.Jörg Frömel

Assoc. Prof.Shinya Yoshida

ProfessorShuji Tanaka

Assoc. Prof.Hideki Hirano

Sr Res Fellow

S. Tanaka LaboratoryDepartment of Robotics & Microsystem Integration CenterTohoku University

Research menu in 2017-2018• Sensor systems for human-friendly robots• Frequency control devices (SAW and BAW devices)• Advanced inertial sensors• Acoustic sensors• Integrated biosensors• Piezoelectric thin films and devices• Heterointegration and wafer-level packaging technology• MEMS process tools (ALD, wafer bonder etc.)

In cooperation with

mems tohoku

memsの新しい話題 - mems パークコンソーシア …mems の新しい話題 田中秀治...

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memsの新しい話題 - mems パークコンソーシア …mems の新しい話題田中秀治...