Wafer-level HeteointegrationTechnology and its Applications

1

Shuji TanakaProfessor, Department of Bioengineering and Robotics

Director, Micro/Nano Machining Research & Education CenterProfessor, Microsystem Integration Center

Tohoku UniversitySendai, Japan

mems tohoku

魯迅 Lǔ Xùn Studied in Tohoku University

2

Novel 「藤野先生」

This novel is based on Lǔ Xùn’s experiencein School of Medicine, Tohoku University

Lecture room 階段教室, where Lǔ Xùn’ studied, in Katahira Campus

魯迅像

藤野厳九郎像

（former 仙台医学専門学校） in 1904 ~ 1906. 藤野 厳九郎 教授 Prof. Fujino was Lǔ Xùn’ssupervisor.

Lǔ Xùn’s notebook先生 in Japanese老師 in Chinese

MEMS Facilities in Aobayama Campus

3 S. Tanaka Laboratory CleanroomMicrosystem Integration Center

New campus

Subway station(under construction)

Aobayama Campus

Google

Micro/Nano-Machining Research and Education Center (MNC)

Hetero-Integration

4

MEM device

Integrated circuit

Functional material

Si

Ferroelectric/Piezoelectric materialse.g. LiNbO3

Li

Nb

O

Frequency controlOptical modulationParametric oscillationDetectionActuation

ProcessingAmplificationMemoryDetection

Tactile Sensation on Whole Robot Body

5 “Paro”, Intelligent Systems

“RIBA”, Riken

Care robot

Pet robot

Tactile sensor network for home and medical robots enables:

• Contact detection for collision safety• Body contact communication

How to imitate or replace nerve network?

I. Kumagai et al., IEEE/RSJ’12 (2012)

Robot skin

Parallel connection between brain and 107 of tactile receptors

Bus-conenctedtactile sensor

Tactile Sensor Network on Robot

6

MEMS-on-CMOS Integrated Tactile Sensor

M. Makihata, S. Tanaka et al., Sensors & Actuators A (2012)M. Makihata et al., 2012 MRS Spring Meeting

MEMS-CMOS interconnection

Capacitive sensing electrode

Thinned CMOS wafer

7

BCB polymer

Through-silicon groove

I/O pad

1 mm

2.4×2.4×0.3 mm2

Through Silicon Groove (TSG)

M. Makihata, S. Tanaka et al., Sensors & Actuators A (2012)Trapezoidal blade

IO pad

Grooving Insulation & wiring

Polymer filling & planarization

Wafer bonding

Back-grinding & dry etching

Redistribution wire

Contact hole

LSI pad

LSI BEOL layer

Tapered groove

Bottom of tapered groove

TSG backside contact

BCB MEMS sensor

LSI wafer

SiO2

LSI

BCBAu

MEMS

8

M. Makihata, S. Tanaka et al., Sens. Actuators A, 188 (2012) 103-110

Through Silicon Groove formed on ASIC

Data from Integrated Tactile Sensor

9

M. Makihata, M. Muroyama, S. Tanaka et al., 2012 MRS Spring Meeting

1 mm

Integration for Multiband Wireless Front-End

LNA 0/90 ºA/D

A/D

Digital signalprocessor

FilterMixer

Discrete devicesIntegrated devices based on RF CMOS technology

Frequency tuning device

• Integration of acoustic filters andtiming resonators on RF-CMOS

• Integration of many front-end filters formultiband wireless systems

• Frequency tunability enabled byMEMS (e.g. variable capacitor)

Rx

Electro-mechanical components

MEMS-enabled function

10

Electrostatic vs. Piezoelectric ActuationG. Klaasse, R. Puers (KU Leuven), H. A. C. Tilmans (IMEC), SeSens Proc. (2002)

11

Pull-in voltage Touch-down voltage (δ = d0)

Al cantilever:E = 70 GPa, h = 1 μm, l = 100 μm, d0 = 3 μm→ VPI = 25 V

Al/AlN/Al cantilever:AlN E = 320 GPa, d31 = 3.125 pC/N, h= 0.1/0.8/0.1 μm, l = 100 μm, d0 = 3 μm→ Vp = 18.5 VCu/Pt/PZT/Pt cantilever:PZT E = 70 GPa, d31 = 90 pC/N→ Vp = 2.4 V

PZT-Actuated MEMS Switch on CMOS

12

A

C

A B

GND RF I/O GND

Contact

Bias electrode

LSIAl pad

C

BAuPZT

Cu SiO2

Pt

0

1

2

3

4

5

6

7

0 2 4 6 8 10D

efle

ctio

n [μ

m]

Voltage [V]Driving voltage (V)

Def

lect

ion

(μm

)

Matsuo, Moriyama, Esashi, Tanaka (Tohoku Univ.), IEEE MEMS 2012

PZTPtAu

PZT-Actuated MEMS Switch on CMOSMatsuo, Moriyama, Esashi, Tanaka (Tohoku Univ.), IEEE MEMS 2012

Signal line

A-1. Fabrication of PZT MEMS structure

PolymerA-2. Polymer spin-coating

PZTPt drive electrode

Si wafer

Si wafer

Au

PolymerB-2. Polymer spin-coating

B-1. Fabrication of electrodes and pads on IC

Au

IC wafer

IC wafer13

Tunable BST Varactor on CMOS Power Amp

14

0

0.1

0.2

0.3

0 0.5 1 1.5 2Frequency (GHz)

Adm

ittan

ce (S

) Bias 0 V Bias 8 VTransferred BST varactor

Au electroplated inductor

Au electroplated inductor Transferred BST varactorBCB bonding polymer

0.18 μm CMOS power amplifier (Kyushu Univ.)

Bio-Electrochem LSI with Diamond Electrode

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Transferred B-doped diamond film(Working electrode)

PDMS flamePDMS potting

Au wire

LSI

BCB bonding polymer

LSI pad

Diamond electrode

Au inter-connection

T. Hayasaka, S. Yoshida … S. Tanaka, IEEE MEMS 2014, pp. 322-325

Electrochemical Biosensor Array

Bio-LSI chip

Multi-project wafer LSI chip Electrode array Electrode

250 μm

Electrochemical bio-activity sensing

Subred SubOX O2CO2

Enzyme kinetics analysis

Cell respiration activity

Immunoassay for diagnostics

Cell-based assay for environmental monitoring16 Collaboration with Prof. Matsue, Tohoku University

Wafer-Bonding-Based Integration: Problems

17

MEMS gyroscope

ASIC

Steven Nasiri and Martin Lim,InvenSense, Inc.

VacuumAlGe eutectic boding

Market share > 20 %for 3-axis gyros in mobiles (2011)

Difference in die sizeMEMS

ASIC

Vacuumor N2

Metal seal

Interconnect

Combo Sensors

18 Photographs: Romain Fraux (System Plus Consulting)

STMicroelectronicsLSM9DS0 (4×4 mm2)5 dies- Accelerometer- Gyroscope- Magnetometer- 2 ASIC

BoschBMX055 (3×4.5 mm2)5 dies- Accelerometer- Gyroscope- Magnetometer- 2 ASIC

InvenSenseMPU-9250 (3×3 mm2)2 dies- Integrated 6-axis

inertia sensor- Magnetometer

Combo sensor:3-axis accelerometer3-axis gyroscope3-axis magnetometer (e-compass)

System in Package(SIP)

Selective and Multiple Die Transfer

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Glass support waferMEMS

ASIC

(1) Wafer bonding

(2) Laser irradiation THG Nd:YVO4 laser (λ = 355 nm)

Polymer

(3) Selective die transfer Reusable Reusable

180⁰C

FBAR and Sustaining Amplifier IC

20S. Taniguchi et al. (Taiyo Yuden),IEEE Ultrasonics Symposium 2007

VDD

FBAR(2 GHz)

Bias circuit

Outputbuffer

VSS

Sustaining Amplifier IC

FBAR

1 mm

2 mmAu seal ring (fly-cut)

Interconnectbump (fly-cut)

Designed and fabricated byAsahi Kasei Microelectronics

Selective and Multiple Die Transfer

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FBAR (1×1 mm2) ASIC (2×2 mm2)

Multi-project LSI wafer (Shot size 20×20 mm2)

Our ASIC(2×2 mm2×4 dies)Asahi Kasei Electronicsor Kyushu University

FBAR (1×1 mm2)Taiyo Yuden

FBAR(Dummy for bonding)

4 times of die transfer were demonstrated using the same MEMS wafer.

K. Hikichi … S. Tanaka, IEEJ Sensor Symposium 2013

Integrated/Packaged 2 GHz FBAR Oscillator

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-160

-140

-120

-100

-80

-60

-40

-20

-180

Phas

e no

ise

(dBc

/Hz)

Carrier 1.9624 GHz

100 1k 10k 100k 1M 10M Offset (Hz)

LiNbO3 on IC One-Chip SAW OscillatorS. Tanaka (Tohoku Univ.) et al., IEEE Trans. Ultrason. Ferroelectr. Freq. Contr., 59, 8 (2012)

Integrated SAW oscillator500 µm

LSISAW resonatoron 128 Y LN

Au bump23

Phase Noise of One-Chip SAW Oscillator

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Δf −1

Δf −3

Δf 0f0/(2Q) ≈ 200 kHzQ ≈ 1250

502.5 MHz

-110

-120

-130

-140

-150

-160

-170

10 kHz 100 kHz 1 MHzFrequency offset

dBc/Hz

TV White Space Cognitive Radio

25

40 ch × BW 6 MHz= 240 MHz

Ch.13

Sendai

470 MHz 770 MHz

Ch.62

NH

K

NH

K

(E)

TBC

仙台

ミヤギ

東日

本

Ishinomaki

710 MHz

DigitalTV band

2013

.12

2012

.12

Mon

thly

ave

rage

traf

fic (G

bps)

×2.2/year

2013

.9

2013

.6

2013

.3

2012

.9

2012

.6TV white space

TV white space cognitive radiocommunication (IEEE 801.11af)

Monthly average traffic of mobilecommunication in Japan

Design of Tunable SAW Filter (Chiba Univ.)

260.980.98 0.98 0.98 0.98

0

10

20

30

40

Frequency (GHz)

Inse

rtion

loss

(dB)

Y: SAW resonatorC: Varactor

10 SAW resonators and 10 varactors integrated on 42º Y LiTaO3

A B C’ CCp1 Small Large

Cp2 Large Small

Cs1 Small Large

Cs2 Large Small

Relationship between capacitance and bandwidth

Simulation

M. Inaba, T. Ohmori, K. Hashimoto (Chiba Univ.), Jpn. J. Appl. Phys., 52 (2013) 07HD05

tan δ

Nor

mal

ized

ε

1

3

5

7

0Applied voltage

εtan δ

Hetero-Integration of BST Varactor

(Ba1−xSrx)TiO3

(Murata Mfg.)

SAW resonator

BST varactor

Al

BSTPt

AuAu

Pl Pl

42º Y LiTaO3

Pt

Sapphire sub.

Pt-Au bonding

AuBST

LT sub.

IDT AuLT sub. LT sub.

Si Sub.

LT sub.

Pt

BST is deposited at 600ºC or higher.

Sapphire wafer removal27

BST varactor

Laser

Laserpre-irradiation

Transferred BST on LT SAW Wafer

28

Au

BST

SAW

reso

nato

r

LiTaO3

4 mm × 4 mm

Bandpass Characteristic and Application

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CS1, CP1: 0 V, CS2, CP2: 7 V

CS1, CP1: 7 V, CS2, CP2: 0 V

1.041.021.000.980.96Frequency (GHz)

0

-10

-20

-30

-40

-50

Inse

rtio

n lo

ss (d

B)

Tunable SAW filter inside

Antenna port

Rx Tx

Tunable SAW filter

DA converter

TV white band cognitive WiFisystem using tunable filter (NICT)

Summary

30

1. Devices are always getting smaller and more functional,and wafer-level heterointegration technology is a powerfulmethod beyond SiP (System in Package) approach.

2. A network tactile sensor for human-friendly robots wasconstructed by the wafer-level adhesive bonding of acapacitive force sensor and a LSI.

3. Functional thin films (PZT, diamond etc.), which are notcompatible with CMOS, were transferred from Si wafers toLSI wafers, and integrated devices were prototyped.

4. A one-chip tunable filter for TV white space cognitivewireless LAN was made by the monolithic integration ofSAW resonators and BST varactors. The BST thin film wastransferred from a sapphire wafer to a LiTaO3 wafer bylaser-assisted debonding technology.

S. Tanaka Laboratory Members

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特任教授⾨⽥ 道雄

教 授⽥中 秀治

准教授（μSIC）室⼭ 真徳

助 教塚本 貴城

助教（μSIC）平野 栄樹

助教（WPI-AIMR）吉⽥ 慎哉

Project Prof.Michio Kadota

ProfessorShuji Tanaka

Associate Prof.Masanori Muroyama

Assistant Prof.Takashiro Tsukamoto

Assistant Prof.Hideki Hirano

Assistant Prof.Shinya Yoshida

Professor 6Staff 6PhD course student 9Master course student 6Undergraduate 7Research student 2Visiting researcher 3

In total 42

Collaborators 5+(Microsystems Integration Center)

Please visit S. Tanaka Laboratory websiteat http://www.mems.mech.tohoku.ac.jp/index_e.html

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