PIEZOMATERIALS @LETI Piezo background by Pierre and … · 2019. 7. 5. · Guillaume...
Transcript of PIEZOMATERIALS @LETI Piezo background by Pierre and … · 2019. 7. 5. · Guillaume...
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Process capability
Piezo background
PIEZOMATERIALS @LETI
Material trends
Piezoelectric effect was first proven in 1880
by Pierre and Jacques Curie
Guillaume [email protected] l Prototyping Pilot Line Workshop l Friday, June 28th 2019
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INTRODUCTION MEMS AT LETI
CEA-LETI : A LEADING MEMS R&D LAB WORKING FOR INDUSTRY
30 YEARS BACKGROUND IN MEMS
200 PEOPLE involved in MEMS (sensors, actuators, RF, packaging, process, characterization, IC design)
COMPLETE 200MM PILOT LINE FOR M&NEMS MANUFACTURING
330 PATENTS PORTOFOLIO IN THE MEMS FIELD
35 NEW PATENTS AND 100 PUBLICATION PER YEAR
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Piezo
stack
ACTUATORS
SENSORS
OPTICAL MEMS
HAPTICS
RF FILTERS
FLUIDIC BIO
pMUT
ENERGY HARVESTING
Micro-pump and
biological cells
manipulation
Varifocal Lens
Pyroelectric sensor
PZT and AlN actuation
Micro-miror
Solid Mounted Resonator
PIEZOMEMS
Guillaume Rodriguez l Prototyping Pilot Line Workshop l Friday, June 28th 2019Guillaume Rodriguez l Prototyping Pilot Line Workshop l Friday, June 28th 2019
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FROM MATERIAL DEPOSITION TO SYSTEM INTEGRATION
Characterizations
Prototyping
3D assembly
MEMS Fabrication
Electronic design
LETI covers the wholechain of development
Packaging
MEMS Design
New materials deposition
Process Integration
Material Nano-Characterization
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SENSING
3 MAIN PIEZO FAMILIES AT LETI
State of the art Solgel PZT properties
Several PZT device demonstrations : variable focus lens, micro-pump, optical scanner
2 Technological Transfers to and to a World-Class Foundry
Variable focus lens
Optical scanner
Sol-gel PZT Technology
7 years of industrial development with high maturity process, reliability, throughput…
Several AlN device demonstrations: BAW filter, High-SNR µphone, haptic sensor
Technological Transfer to a World-Class Foundry
PVD AlN Technology
AlN-on-glass for haptic
High-SNR microphone
Smart-cut crystal transfert
Strong collaboration with Soitec
Smart-cut LiNbO3 Technology
ACTUATING ACOUSTIC
SMR Filters
High electromechanical coupling
Kt2=26%
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TOOL SET
PZT PROCESS @LETI
Successfully transferred to 2 main foundries
SOL-GEL DepositionLead zirconium titanate
APPLICATIONS
LETI STRENGHT
A generic 200mm piezo test vehiculeON GOING DEVELOPMENT
MEMS actuatorsHigh K, High piezo coef
Properties
Piezo-ferro-electric
High piezo coefficient
High Pyro coeff
High K
Variable focus lens Micro-pump Optical scanning
Replace PZT by a Lead-Free piezo
A major challenge
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Improve crystallinity :
Smart interface
MOCVD AlN
Doped AlN :
Co-sputtering and conventional sputtering
Composition screening, versatile
AlN PROCESS @LETI
TOOL SET PVD DepositionAluminium Nitride
APPLICATIONS
LETI STRENGHT ON GOING DEVELOPMENT
NEMS sensors, Acoustic Wave Devices
Properties Sigma fxp
Thickness 200nm to 10µm
Thickness NU% < 0,5%@1σ
FWHM [002] < 1,5°
Dielectric constant = 10-11
Dielectric losses <0,1%
e31,f 1 C/m2
d31,f -2,5 pm/V
SMR Filters µCantilever Membranes
High maturity process, reliability, throughput on AlN process
Co-sputtering capability MSQ module : AlN doped
EVATEC ClusterlineTMSPTS Sigma® fxP
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TOOL SET APPLICATIONS
LETI STRENGHT ON GOING DEVELOPMENT
Reinhardt et al., IUS 2014
1st demo of a sub-micron-thick single-crystal FBAR
k² = 39.2 % and Q = 250 @ 2.5 – 3 GHZ
Q-factor still limited and Strong temperature dependence
Smart-cut approach
Direct deposition approachMOCVD national research program
Sputtering trials
PLD investment @Leti
Strong background in RF Filters
Strong background in BONDING
Collaborations with key players
LNO / LTO PROCESS @LETI
NEW
100mm to 200mm
5G challenges
Acoustic Wave DevicesSmart-cut Process
Overcoming limitations of wafer thinning
switch to Smart CutTM
What can offer this approach ?
High crystal quality at low thickness
But strong challenges
Learning curve on acoustic optimizations
(Q-factors, parasitics, T°C compensation)
Courtesy Solmates
Kt2 AlN = 6,5%
Kt2 LiNbO3 = 45%
XRD pattern : no significant crystal difference is noticed
between the lattice structure of the transferred LiTaO3
Gorisse et al , 2018 IEEE International Ultrasonics Symposium (IUS)
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to measure MEMS deflection under applied voltage and extract piezo coefficient d31
Wyko interferometer
Laser interferometryto measure e31 piezo coefficient
aix4PB system
Automatic 8’’probers for electrical characterization
C(V)Permittivity and dielectric losses P(V) Ferroelectric polarization I(V) leakage current and breakdown voltage
Wafer level electro-mechanical displacements analysis
Electrical characterization
MATERIALS AND DEVICES CHARACTERIZATION
X-Ray Diffraction Optical profilometry WDXRF spectrometer
3D scan & Local stress Composition and film thicknessstructural characterization
In line piezo layer metrology
8 inch wafer Double Beam
Laser Interferometer
Effective piezo coeficient d33,f
Fast measurement
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• Thin film piezoelectric material & technology knowledge
• High maturity processes, improvements done on reliability, repeatability, throughput…
• Background on process but also on design
• Broad range of deposition and characterization tools
• Investissement in emerging PLD technology and piezo coef characterization
• On-going research on RF filters
• To overcome limitations of standard AlN
• Higher bandwidth, higher frequencies
• With enhanced AlN (crystal, doped) or new piezo materials (LNO)
• New challenges for PIEZOMEMS
• Lead free materials (KNN, BCTZ,…)
• Transparent piezo stack for haptic
CONCLUSION
Guillaume Rodriguez l Prototyping Pilot Line Workshop l Friday, June 28th 2019
Leti, technology research institute
Commissariat à l’énergie atomique et aux énergies alternatives
Minatec Campus | 17 rue des Martyrs | 38054 Grenoble Cedex | France
www.leti-cea.com
Leti l 2018-09
Thank you for your attention
Contributors for the presentation- A. Lefevre
- G. Le Rhun
- F. Servant
- C. Billard