Study of MEMS Devices for Space Study of MEMS Devices for Space ApplicationsApplicationsApplications Applications

The 24The 24thth Microelectronics WorkshopMicroelectronics WorkshopOctober 2011October 2011October, 2011October, 2011

Maya KatoMaya KatoElectronic Devices and Materials GroupElectronic Devices and Materials GroupJ A E l ti AJ A E l ti AJapan Aerospace Exploration AgencyJapan Aerospace Exploration Agency

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OutlineOutline

Introduction of MEMSIntroduction of MEMS Introduction of MEMSIntroduction of MEMS

ProcessProcess–– FabricationFabrication processprocess

ExamplesExamples–– Data (Process)Data (Process)

–– Sample devices made as an experimentSample devices made as an experiment

(Actuator, Switch and Mirror)(Actuator, Switch and Mirror)

Future activitiesFuture activities

ConclusionsConclusions

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・MEMS fabrication was supported by Nihon University(CST)

Introduction of MEMSIntroduction of MEMS

MEMS:MEMS: MMicroicro EElectrolectro MMechanicalechanical SSystemystem MEMS: MEMS: MMicro icro EElectro lectro MMechanical echanical SSystemystem Advantages of MEMS DevicesAdvantages of MEMS Devices

–– Downsizing and weight saving deviceDownsizing and weight saving deviceg g gg g g•• For microfabrication applied by semiconductor processFor microfabrication applied by semiconductor process•• For integration of structure and electronic circuitFor integration of structure and electronic circuit

–– Implementation of various functionsImplementation of various functionsImplementation of various functionsImplementation of various functions•• For utilizing various physical phenomena such as mechanics, For utilizing various physical phenomena such as mechanics,

electronics, optics, and fluidelectronics, optics, and fluidLow costLow cost–– Low costLow cost

•• Similar to semiconductor process, MEMS can be massSimilar to semiconductor process, MEMS can be mass--produced produced with good and stable qualitywith good and stable quality

Application of MEMSApplication of MEMS Application of MEMSApplication of MEMS–– SSensorensor, Actuator, Biotechnology, Information machines and , Actuator, Biotechnology, Information machines and

equipment, equipment, ・・・・・・・・

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Application of MEMSApplication of MEMS

GMR sensorGMR sensor

microphonemicrophone

gyroscope（position control ）gyroscope（position control ）

(engine control) (engine control)

Biosensor（ driver's condition ）

Biosensor（ driver's condition ）

l til ti

microphone（ communication ）

microphone（ communication ）

infrared sensorinfrared sensor

（ driver s condition ）（ driver s condition ）

acceleration sensor（airbag）

acceleration sensor（airbag）

infrared sensor（tire pressure ）infrared sensor（tire pressure ）

i f di f dinclination sensorinclination sensor

infrared sensorinfrared sensor

crash sensorcrash sensor AE sensor（detection of abnormal sound）AE sensor（detection of abnormal sound）

infrared sensorinfrared sensorinfrared sensor（infrared temperature sensor）infrared sensor（infrared temperature sensor）

Introduction of MEMSIntroduction of MEMS・ High-Density and High-Performance・ Small and lightweight

・ Application of semiconductor process.・ Very minute mechanical structure is created on Si chip. RFRF

Ci itCi it

Si chipSi chipRFRF

CircuitCircuit

SensorSensorMicro

dynamoMicro

dynamo MicroElectroMechanical

Micromachine ＝＋ I t t d i itNew

System

55

Micromachine ＝＋ Integrated circuit Device

Fabrication ProcessFabrication Process

1. Starting material : (SOI wafer)SiO2

Si (Device)g ( )

2. Surface cleaning and HMDSSiO2 (BOX)Si (Device)

Si (Handle)

3. Resist coatingFig.1 Cross section

SiO2

4. Photolithography (Patterning)

5. Etching (Surface: SiO2 )(20mm□ Chip)

Ag ( 2 )

6. Resist removal

AcetoneEthanol ...SC1(NH4OH / H2O2 / H2O)

7. Si Deep RIE (Bosch process; ICP)

Fi 2 T i

SC1(NH4OH / H2O2 / H2O)....

HMDS(Hexamethyldisilazane)

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8. Release : BOX Layer (SiO2)

・MEMS fabrication was supported by Nihon University(CST)

Fig.2 Top view

・ ICP: Inductively Coupled Plasma

Fabrication ProcessFabrication Process

SiO2

7. Si Deep RIE (Bosch process; ICP) 8. Release : BOX Layer(SiO2)

Si (Device)SiO2 (BOX)

Si (Handle)

Fig.7-1 Cross section Fig.8-1 Cross section ICP Release

Fig.7-2 Top view Fig 8-2 Top viewg p Fig.8 2 Top view

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Example Data Example Data 【【 Effect of HMDS Effect of HMDS 】】

・ SiO2 Etching pattern

OFPR800LB酸化膜・HMDS処理効果

（凸面）Effect of HMDS treatment

HMDS未処理 HMDS処理(10min.)Without HMDS

HMDS Coating (Vapor for 10 minutes )

m)

Without HMDS

0 5

1

1.5

さ(μ

ｍ）

f S

iO

(µm

2

0 5

0

0.5

00

44

88

32

76

20

64

08

52

SiO

2膜

厚Th

ickn

ess

of

-0.5

3.8

3

3.8

3

3.8

3

3.8

4

3.8

4

3.8

5

3.8

5

3.8

6

3.8

6

位置(ｍｍ）

T

Location (mm)

88

Sharp HMDS Coating (Vapor) ・ HMDS: Hexamethyldisilazane [(CH3)3Si]2NH

Example Data Example Data 【【 Si Deep RIE; ICP Si Deep RIE; ICP 】】

S (Width) ・ Parameter: (Depo – Etch) Cycle( p ) y

【 L & S TEG 】図1 1 D-E条件（1-2 サイクル数）のＳ幅による深さ依存【 L & S TEG 】【 L & S TEG 】◆ Depo - Etch = 2sec - 4sec

図1.1 D E条件（1 2、サイクル数）のＳ幅による深さ依存

50.00

【 】◆ Depo - Etch = 1sec - 2sec

L (Depth)

30.00

40.00

μｍ

） 150

100

150cyc 100cyc 50cyc（

μｍ）

10.00

20.00

深さ

（

50

25

50cyc 25cyc

L

0.00

0 10 20 30 40 50 60

S幅( ）S (μｍ）

99

S幅(μｍ）S (μｍ）

Example Data Example Data 【【 Si Deep RIE; ICP Si Deep RIE; ICP 】】

◆ Depo Etch = 1sec 2sec【 L & S TEG】 SEM images SEM images

◆ Depo - Etch = 1sec - 2sec

25cyc

S= 3um S= 5um S= 7um S= 10um

50cyc

S 3um S 5um S 7um S 10um

100cyc

1010

Example Data Example Data 【【 Si Deep RIE; ICP Si Deep RIE; ICP 】】

◆ Depo - Etch = 1sec - 2sec【 L & S TEG】 Cross sectionCross section

◆ Depo Etch 1sec 2sec

25cyc

S= 3um S= 5um S= 7um S= 10um

50cyc

S 3um S 5um S 7um S 10um

100cyc

1111

Example Data Example Data 【【 Si Deep RIE; ICP Si Deep RIE; ICP 】】

ＳｉＯＳｉＯ２

notchＳｉ

deficient etching Moderate ecching Over etching

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Example Data Example Data 【【 Residual material Residual material 】】

(after BOX Layer etched)

SEM and EPMA SEM and EPMA imagesimages

(after BOX Layer etched) SiSEM

CF

R id l t i lResidual material

C F Al AuC4F8

(protection generation film at ICP)

1313

at ICP)

Example Device (1) Example Device (1) 【【 MEMSMEMS--Actuator Actuator 】】

Suspension Structure Structure pDevice Layer = 35umBOX Layer = 4um

GND +V

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Example Device (1) Example Device (1) 【【 MEMSMEMS--Actuator Actuator 】】

Characteristic Characteristic

【 Voltage vs Stroke 】

Parameter: (Suspension [ Width – Length ])25

Stroke (um)

15

20 5um - 500um6um - 300um6um - 400um

5

106um - 500um7um - 300um7um - 400um

0

0

10

20

30 40

50

60

70

80

90

100

110

1515

Voltage (V)

Example Devices (2) Example Devices (2)

MEMSMEMS--SwitchSwitch MEMSMEMS--MirrorMirror MEMSMEMS Switch Switch

・ Vertical structural typeDevice Layer = 60um

MEMSMEMS Mirror Mirror

◆ Impact test (at 644G,z-axis)yBOX Layer = 4um

◆ Opening-and-closing examination( >100 million times )

p ( , )

( >100 million times )

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Future activitiesFuture activities

Examination Examination –– Phenomena peculiar to MEMS, such as “stiction”. Phenomena peculiar to MEMS, such as “stiction”. –– Improvement of manufacturing technology.Improvement of manufacturing technology.p g gyp g gy–– Ensuring high reliability and evaluation toward space Ensuring high reliability and evaluation toward space

applications.applications.

FutureFutureFutureFuture–– Manufacturing of Manufacturing of MEMSMEMS--ShutterShutter using actuator. using actuator. –– Research and development ofResearch and development of RFRF--SwitchSwitchResearch and development of Research and development of RFRF SwitchSwitch..

・Space components are required to have high quality.

–– Others; Evaluation of Others; Evaluation of commercial MEMS components commercial MEMS components

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;; pptoward space applications.toward space applications.

MEMSMEMS--ShutterShutter

Useful as a tool for the optical /Useful as a tool for the optical / radiationradiation examination onexamination on Useful as a tool for the optical / Useful as a tool for the optical / radiationradiation examination on examination on the ground.the ground.

Light / RadiationShutter cover

Actuator

Si (Device): 35～50um

Light / Radiation Actuator

( )

Th h h l

SiO2(BOX): 2～4um

Through hole20～30um

Si (Handle) 150～250um

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Test Test Sample

RFRF--SwitchSwitch

Useful for switches such as “Synthetic Aperture Radar”Useful for switches such as “Synthetic Aperture Radar” Useful for switches, such as Synthetic Aperture Radar .Useful for switches, such as Synthetic Aperture Radar .

◆ Environment / RequirementEnvironment / Requirement◆ Environment / RequirementEnvironment / RequirementHigh reliability ----- life, Failure, Operational stabilityRadiationRadiation Vibration and shock (Launch)Temperature ----- High, Low, CyclePracticality -------- Small and lightweight, Quantity yield, Low cost・・・・

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RoadmapRoadmap

【Design and Fabrication】in JAXA

FY2010 FY2014～FY2011 FY2012 FY2013

Basic technology Technical extension / Application expansion Standardization

◆ Application to devices

◆ R h f li bilit d t h i l bj t

　　in JAXA gy

MEMS-Shutter etc. (for an Optics / Radiation test)

Fabrication, Examination, Evaluation Device development

pp p

TEG Test useSolutionSolution

ofoftechnicaltechnical ◆ Research of reliability and technical subjects

【 】

･･･→ RF-Switch(for missions, for control, etc. ) Solution of technical subjects

(turned to space application)

Fabrication of TEG(for reliability assessment)

Research,Examination

technicaltechnicalsubjectssubjects

◆ Gyroscope

【Commercial Parts】 for space application Examination and Evaluation

use in spaceEnvironment / Radiation examination Test useTAG202, etc.

Environmental test

Standardization

(Data source for an FPGA actual proof)

UseUseinin

◆ New device for application

【Related elements / Means】

RF-Switch, etc. Research,

Examinationspace application

Measurement of the characteristicEnvironment / Radiation examination

SpaceSpace

【Related elements / Means】Nihon University

(support)

(Cooperation)

new external organization

External organizationInstitute of Space and Astronautical Science (ISAS)

2020

　

Enhancing examination / evaluation equipments

new external organization(Equipment and technology)

ConclusionsConclusions

Design / Fabrication environment of fundamental MEMSDesign / Fabrication environment of fundamental MEMS Design / Fabrication environment of fundamental MEMS Design / Fabrication environment of fundamental MEMS was acquired.was acquired.– Micro fabrication process technology with a minimum width of

3um (TEG pattern) was acquired3um (TEG pattern) was acquired.– The electrostatic type actuator was manufactured and the

characteristic was acquired.– Technology was applied and other devices were made as anTechnology was applied and other devices were made as an

experiment. FutureFuture

Make an useful MEMS shutter as an experiment to a terrestrial– Make an useful MEMS shutter as an experiment to a terrestrial examination (radiation and optics).

– Study the failure mechanism and reliability peculiar to MEMS such as “stiction”.as stiction .

– Promote research and development of RF-Switch based on the results.

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Thank you for your attentionThank you for your attention

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