How to make an old material class the cutting edge …...Highly robust design Low operation voltage

High volume piezoelectric thin film production process for microsystems (2010-2012)High volume piezoelectric thin film production process for microsystems (2010-2012)

How to make an "old" material class the cutting edge

Frode Tyholdt (SINTEF)

FP7 piezoVolume – High Volume Piezoelectric Thin Film Production Process for Microsystems


• Add-on technology to silicon Micro Electromechanical Systems (MEMS)

• Has been under research for 20-25 years and is currently being commercialized

• Ink-jet printing and medical ultrasound technology drivers

• 2 talks in COMS 2012 about piezoMEMS• poLight (end user)• Solmates (piezo thin film deposition

technology)

Piezoelectric microsystems (piezoMEMS)


• Printer industry: This is clearly the biggest market and is partly already established today (2011 – 2012)

• HDD read write heads adjustment: The market break through is expected this year (2012)

• Various telecommunication applications: Depending on the application the markets will start from now to the next 2 years (2012 –2014)

• Automotive market: telemetry sensors, like tire pressure measurement. This market is estimated to come in the next years. (2015)

• Small speakers: To be integrated directly into MEMS.

• Energy harvesting: feeding power to small transmitters etc. This market is estimated to go faster than expected in the next years (2015)

• Non-ink printing applications: This concerns mainly printing of electronic materials. This market is estimated to be even 9 times higher than the ink printing market. (2014)

Emerging applications / MEMS

ColorWave 650 ink-jet printer by Océ


• Biosensors: Detection via resonance frequency change from molecule load. Market will come soon (2013)

• HF ultrasound: Development of a high frequency scanner (10-30 MHz) skin cancer detection.

Examples of applications / Medical

Medical ultrasonic transducer by Vermon


Piezoelectric materials

• The ability to produce a voltage output in response to an applied stress

• The ability to produce a strain output (or deformation) in response to an applied voltage.

• Important piezoelectric materials– Pb(Zr,Ti)O3 (PZT)

– Quartz, AlN, ZnO, (Na,K)NbO3

Bulk piezoceramic parts from Ferroperm piezoceramics A/S (DK)


Direct effect (sensors and energy

harvesting)

• Vibration sensor• Accelerometer• Microphone• Photoacoustic sensors• Energy scavenging from

vibrations

Converse effect (actuators)

• Vibration damper• Optical scanner• Optical switch• Micro positioning• Micro and nano probes• Switch/relay, RF switch• Valve• Droplet ejector, inkjet

Converse effect (with resonant

ultrasound excitation)

• Ultrasonic stator • for micromotor• Liquid delivery

Both effects in at resonance

(transducers)

• Ultrasonic imaging• RF filters• Transformers• Proximity sensors

piezoMEMS – a technology with many facets


piezoMEMS is an enabling technology

Bulk PZT

Comb drive Pitch 8 µm, gap 1 µmComb drive Pitch 8 µm, gap 1 µm

100 MPa

bar

MPa

Pa

nm mmμm

Bloc

king

pr

essu

re

Stroke length

Actuator comparison (3 - 40 V)

"Piezoelectric actuation is theholy grail of micro-optics"Olav Solgaard, Stanford University


MEMS actuation case 1

www.polight.com

• poLight autofocus lens– High speed and ultra low power

autofocus piezoelectrically actuated lens

COMS 2012 talk on Monday


MEMS actuation case 2 – Tunable infrared filter for gas detection

Precisely tunable gap

Finished IR filter

Continuously tunable, Fabry-Perot-based high precision filter for infrared spectroscopy

Wavelength ranges: 1.2 – 2.4μm or 7-14μm

Highly robust design

Low operation voltage <25V

Low cost, wafer scale production

10 10.5 11 11.5 120

0.5

1

1.5

25V

10V

15V20V

25V

PZT actuator

Wavelength (µm)

Pow

er (a

rb. u

nits

)

FTIR measurement

Thor Bakke et al., SINTEF MiNaLab


MEMS actuation case 2 – 2D micromirror for laser beam scanning

• Static tilt possible (non-resonant)

• High frequency (~10kHz)

• Planar (~10nm peak-to-valley)Thor Bakke et al., SINTEF MiNaLab


Cool! – what do I need to produce these?


The main challenge

Convert this... into this

20 mm thick PZT ceramic transducer 2 μm thick PZT thin film onto 325 μm silicon

....and retain the material quality= 20-25 years of research

through integration with silicon wafers


The piezoVolume piezoMEMS base process

A 150 mm piezoMEMS wafer


piezoMEMS design software piezoMEMS device fabrication procedures(wafer level)

PZT thin film deposition toolsand procedures

Automated chemicalsolution deposition tool

Sputtering tool

In-line quality monitoring tools

Packaging and integration with electronics

End piezoMEMSproduct

Fabrication proceduresDesign handbook

Bottleneck 3 Design tools

Bottleneck 1 High volume PZT deposition

Bottleneck 2In-situ quality control

FP7 piezoVolume (2010 – 2012)High volume piezoelectric thin film production process for microsystems5,14 M€ project

Project scope stops here


piezoMEMS design software piezoMEMS device fabrication procedures(wafer level)

PZT thin film deposition toolsand procedures

Automated chemicalsolution deposition tool

Sputtering tool

In-line quality monitoring tools

Packaging and integration with electronics

End piezoMEMSproduct

Fabrication proceduresDesign handbook

piezoVolume – partners

VERMON


The piezoVolume base processes

3 electrode configurations

Standard

Interdigital

Cross-routing enabled


piezoMEMS design and fabrication rules

• Tool integration in lab – CMOS compatibility can be obtained

• Material specifications and design guidelines– Material parameters

– Design guidelines and process limitations

– Basic definition of lithographic masks

• Most of it public


piezoMEMS modelling tool• piezoMEMS modelling tool

– 3D parametric library of standard piezoMEMS components

– Integration with FEM software– Material parameters included in process

design kit (PDK)

• Process emulation (virtual manufacturing)– 2D masks + description of fabrication process

to create a voxel based 3D solid model.

• Virtual manufacturing– Save Money by finding problems before

fabrication.– Enhance communication with highly detailed,

interactive 3D models.– Reduce time-to-market and gain a

competitive advantage.– Improve documentation and reduce

document creation effort.– Enhance Yield through improved design rules

and defect modelling. Virtual manufacturing of MEMS bond pads and comb drive.Courtesy X-FAB Semiconductor Foundries, AG.

Beam (in green): 400 x 50 um^2, 3um thickE=1.6e5 MPa, =0.2

Piezoelectric material (in magenta):300 x 50 um^2, 1um thickElastic-AnIso

piezoMEMS beam in Coventorware ARCHITECT.


Process design kit (PDK)

• A Library of process emulation files (*.proc) define foundry-specific processes

• Material property database (*.mpd) provides process-specific values associated with materials

• Layout template file (*.cat, *.gds) contains geometric and process descriptions for pre-defined MEMS elements

• Library of parametric and non-parametric elements support schematic and physical design (optional)

• Link to design handbooks including validated MEMS design rules, detailed process information and design case studies are available upon request

Process Flow of the piezoVolume PZT process represented in CoventorWare


Deposition tools - sputtering

• New hot chuck sputtering add-on for Oerlikon’sClusterline 200 II production tool for in-situ sputtering of PZT

• Throughput goal: 3-4 wafers/h*μm on 200 mm wafers (67 nm/min)

• Very high performance obtained!– 300 % increase from project start

Oerlikon Systems Clusterline 200 II

Hot chuck during sputteringPiezoelectric transversal coefficient e31,f for sputtered PZT on200 mm wafers


Deposition tools – CSD

• CSD = coating of metal organic solution and crystallize by RTP

• RTP integrated into coater cluster tool

• Throughput goal– 4 wafers/h μm on 200 mm wafers (67

nm/min)

Solar-semi coating cluster


Current challenges

• Film defects

• Uniformity of parameters

• Reproducibility of parameters


In-line quality monitoring

aixACCT double and single beam laser interferometer for quality monitoring

Wafer mapping of d33,f using aixPlorer data management and analysis software

• Based on laser interferometry for measuring displacements

• Automatic measurements through electrode mask layout

– Parameter/coefficient tracking

Test pad positions in recipe editor


piezoVolume devices – Oce ink jet

• Ink jet for printing

ColorWave 650 ink-jet printer by Océ

0

2

4

6

8

10

12

14

16

18

-60 -40 -20 0 20 40 60Voltage (V)

Def

lect

ion

(nm

/V)

CSD layer from third partyPV209


piezoVolume devices – Sonitor microphones

• Piezoelectric ultrasonic transducer (pMUT)

– Medical

Medical ultrasonic transducer by Vermon

Vermon


piezoVolume devices – Sonitor microphones

• Ultrasonic microphone for indoor positioning system


piezoMEMS competence centre

• The competence centre aims to act as contact point for interested parties and covers the whole production process for piezoelectric microsystems

– Long experience in piezoMEMS– Experienced project partner

– Deposition process and tools for high-performance PZT thin films on silicon wafers– Modelling software specifically for piezoMEMS– Modelling of device ideas and design assistance– Evaluation of alternative processing routes– Testing services and sophisticated testing equipment– Manufacturing of prototypes– Small scale production using 150 mm wafers (now) and 200 mm wafers (soon)

[email protected]


Project status

• Project started Jan 1st 2010

• Modelling tools– piezoMEMS PDK for Coventorware

available from COVENTOR

– Further developments in 2011 – 2012

• Deposition tools– Good results. More to come in 2011 –

2012

• In-line quality monitoring tool– Tool qualification finished

– Further developments in 2011 – 2012


Check status atwww.piezovolume.com


Acknowledgements

The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2010-2013) under grant agreement n°229196

Thank you!

How to make an old material class the cutting edge …...Highly robust design Low operation voltage

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