rf-mems technology: progress status and commercial outlook · high m etal s tre ss a nd hi gh...
Post on 14-May-2020
3 Views
Preview:
TRANSCRIPT
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 1Microwave & RF 2013
RF-MEMS Technology: Progress Status
and Commercial Outlook
Technologie MEMSRF: état d'avancement et
commercialisation
Fabio COCCETTIFialab / LAAS-CNRS
Toulouse
10 & 11 avril 2013
Paris Expo - Porte de Versailles
Le salon des radiofréquences, des hyperfréquences,
du wireless et de la fibre optique
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 2Microwave & RF 2013
LAAS at Glance:
µ/N Systems TechnologyRF-MEMS @ LAAS (2000 – present)
15 PhD Thesis
7 Post-Docs
Funding Agencies:
ANR, EC (FP6), DGA, Region MP
Main Partnerships:
Fialab - ThalesAleniaSpace – CNES -
LETI – IHP - …
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 3Microwave & RF 2013
Fialab at Glance:REBRANDING
NOVA MEMS became FIALAB starting from January 1st 2013
����
Tests and analyses laboratory.
Our first excellence field is
MEMS/Microsystems
��Enlarging business BEHOND
MEMS
to major industrial markets:
Embedded systems and
Mechanical Parts.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 4Microwave & RF 2013
Outline
• RF-MEMS technology progress status at glance
• R&D Methodologies and Achievements
• Conclusions and Perspectives
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 5Microwave & RF 2013
Technology Maturity and Adoption
Gartner Hype cycle
Source: Gartner Research (1995)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 6Microwave & RF 2013
20111st commercial
consumer
electronics RF-
MEMS1995-98RF-MEMS goes
viral in R&D
environment
Source: Based upon WTC’s (2008) (now IHS – iSuppli )
Technology Maturity and Adoption
Gartner Hype cycle for « RF-MEMS Technology »
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 7Microwave & RF 2013
20111st commercial
consumer
electronics RF-
MEMS1995-8RF-MEMS goes
viral in R&D
environment
Source: Based upon WTC’s (2008) (now IHS – iSuppli )
Technology Maturity and Adoption
Gartner Hype cycle for « RF-MEMS Technology »
Bulck Micromachining
(K. Granier et al. 2000)IN
OUT
IN
OUT
High Power RF MEMES
(D. Dubuc et al.2003)Mm-wave MEMS
(V. Puyal et al. 2009)Switch Ohmic (RS)
(P. Pons et al 2010)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 8Microwave & RF 2013
Source: Slocum, M.S., ‘Technology Maturity Using S-curve Descriptors', TRIZ Journal, April 1999
Technology Maturity and Adoption
S-Curve
> 1 Billion USD
> 1 Million USD
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 9Microwave & RF 2013
Commercial RF -MEMS Components
Source: Radant MEMS switch
Source: Wispry MEMS tunable digital capacitor
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 10Microwave & RF 2013
Timeline of MEMS devices
Source: R. Grace Associates (2012)
Year
19
54
19
55
19
56
19
57
19
58
19
59
19
60
19
61
19
62
19
63
19
64
19
65
19
66
19
67
19
68
19
69
19
70
19
71
19
72
19
73
19
74
19
75
19
76
19
77
19
78
19
79
19
80
19
81
19
82
19
83
19
84
19
85
19
86
19
87
19
88
19
89
19
90
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
20
07
20
08
20
09
20
10
20
11
20
12
20
13
Product
Pressure Sensors 36
Accelerometers 20
Nozzles 24
Photonics/Displays 25
Bio/Chemical Sensors 25
Radio Frequency (R.F.) 12
Gyros/Rate Sensors 22
Micro Relays 27 34
Legend: Discovery Product Evolution Cost Reduction Full Commercialization Elapsed Time in Years
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 11Microwave & RF 2013
Timeline for MEMS devices Commercialization
Product DiscoveryProduct
EvolutionCost
ReductionFull
CommercializationDiscovery to Commercialization
Pressure Sensors 1954-1960 1960-1975 1975-1990 1990 36
Accelerometers 1974-1985 1985-1990 1990-1998 1998 20
Nozzles 1972-1984 1984-1990 1990-1996 1996 24
Photonics/Displays 1980-1986 1986-1998 1998-2005 2005 25
Bio/Chemical Sensors 1980-1994 1994-2000 2000-2005 2005 25
Radio Frequency (R.F.) 1994-1998 1998-2002 2002-2006 2006 12
Gyros/Rate Sensors 1982-1990 1990-1996 1996-2004 2004 22
Micro Relays 1977-1982 1993-1998 1998-2004 2004-2011 27-34
Source: R. Grace Associates (2012)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 12Microwave & RF 2013
Failure mechanism Failure defect Failure mode Failu re cause
1 Dielectric charging of the insulator
Non-permanent stiction -Drift in C-V, Vpi, Vpo -Dead device
2. Electric field charge 3. Radiation 4. Air-gap breakdown 5. Electron emission
2 T-induced elastic deformation of the bridge
Non-permanent deformation of the bridge (restored when T-source is removed), possibly stiction
-Drift in C-V, Vpi, Vpo -Dead device
1. Environment T 2. Different CTE 3. Power RF signal induced T 4. Non uniform T
3 Plastic deformation of the bridge Permanent deformation, possibly stiction -Drift in C-V, Vpi, Vpo -Dead device
1. Creep 2. Thermal induced charges in
material properties (for T > Tc)
4 Structural Short (electrical and non-electrical connections)
Particles, shorted metals, contamination, remains of sacrificial layer, stuck bridge
Anomalous or dead device
- Contamination, particles, remaining sacrificial layer
- Wear particles - Fracture - Lorenz forces - Shock
5 Capillary Forces Stiction Dead device Humidity (Package leaks)
6 Fusing Opens, roughness increase Dead device High RF power pulses, ESD
7 Fracture Broken bridges or hinges Dead device • Fatigue • Brittle materials and shock • High local stresses and shock
8 Dielectric breakdown Dead device, possibly stiction Short between the bridge and the actuation electrodes
• ESD • Excessive charging of the
insulator
9 Corrosion Dendrites formation, oxidation, changes in color
-Drift in Rc C-V, Vpi, Vpo -Dead device
• Humidity, enhanced by bias • Corrosive gases induced
chemical reaction (ex. oxidation)
10 Wear, Friction, Fretting corrosion
Surface modifications, debris, stiction -Drift in Rc C-V, Vpi, Vpo -Dead device
Rough Surfaces in sliding contact
11 Creep Deformation of the bridge in time -Drift in C-V, Vpi, Vpo -Dead device
High metal stress and high temperature, creep sensitive
12 Equivalent DC voltage Self biasing stiction -Drift in C-V, Vpi, Vpo -Dead device
High RF power including spontaneous collapsing or stiction of mobile part
13 Lorenz forces Self biasing stiction Anomalous switching behavior
• High RF power in two adjacent lines
• External magnetic field
14 Whisker formation Bumps in metal, holes in insulator on top of metal layers, etc
Anomalous down capacitance
High compressive stress in metal resulting in grains extrusions, might be enhanced
15 Fatigue Broken bridges and hinges, cracks, microcracks
Shifts in electrical and mechanical properties
• Large local stress variations due to motion of parts
• Enhanced probability of cracks
16 Electromigration Cracks, opens, thickness changes in metal lines
Increase of resistance, opens, shorts
High current density
17 Van der Waals forces Stiction Dead device Smooth and flat surfaces in close contact
18 Electric field-induced meniscus Stiction Anomalous or dead device
Residual layer of water (due to residual RH)
Failure Mode Effect Analysis (FMEA) Application Based
- Movable Thin membranes
- Metal-to-Metal Contact
- Dielectric-to-Metal Contact
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 13Microwave & RF 2013
Major Failures in MEMS Switches
Charging effect
Contact degradationMaterial transfers
Radant MEMS sealing ring
Packaging hermeticity
Decohesion of grain boundaries
Fatigue & creep of movable parts
cantilever
packaging
Source: A. Broue PhD (LAAS-Fialab - 2012)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 14Microwave & RF 2013
Major Challenges / Limitations
� Dielectric charging in electrostatic actuated devices
� Metal contact degradation (welding, wearing,
contamination,…): in resistive switches
� Thermal induced elasto-plastic phenomena (creep-
fatigue): in membrane under high workload
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 15Microwave & RF 2013
Major Challenges / Limitations
� Dielectric charging in electrostatic actuated devices
� Metal contact degradation (welding, wearing,
contamination,…): in resistive switches
� Thermal induced elasto-plastic phenomena (creep-
fatigue): in membrane under high workload
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 16Microwave & RF 2013
Metal-to -Dielectric contact physics
Build up Surface potential
Source: U. Zaghloul PhD (CNRS-LAAS – 2011) - Grant from: RTRA – EDA –Région MP
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 17Microwave & RF 2013
C-V Time zeroC-V after 19 hours
Actuation signal builds up charge in the dielctric resulting in a
SHIFT of the C-V Characteristic
Good Source: EC FP6 (AMICOM 2004-2007)
Dielectric Charging in Capacitive Switches:
Shift of the Vpi/Vpo
Failed
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 18Microwave & RF 2013
Charge injection (through asperities)AFM based investigation techniques
Actuated MEMS
MEMS Bridge
Gold coplanar strips (underpath)
Dielectric layer
Substrate
The AFM is the most suitable tool to simulate
the “local” charge injection process in
electrostatically actuated MEMS
Roughness of electroplated Au
AFM equipment
V
Source: U. Zaghloul PhD (CNRS-LAAS – 2011) - Grant from: RTRA – EDA –Région MP
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 19Microwave & RF 2013
Surface potential Decay Surface potential distribution
tpUp
V
Charge injection
KPFM Methodology in TWO steps
FIRST step: Charge injection
AFM based techniques: Kelving Probe Force Microscopy Charge/discharge kinetic
3
2LSH
Surface potential scanning
1
SECOND step: Surface potential scanning
Space
Tim
e
Su
rface
Po
ten
tial
( )
−⋅∆=∆β
τt
CtC exp0
Array of single point
charge injection
Source: U. Zaghloul PhD (CNRS-LAAS – 2011) - Grant from: RTRA – EDA –Région MP
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 20Microwave & RF 2013
AFM based techniques:Material Evaluation: Silicon Nitride
−=β
τt
UtU s exp)( 0
M. Lamhamdi, et al. J.
Microelectron. Reliab. 46,
(2006)
Surface (Built-in) potential
KPFM
Discharging time-constant
SiNx (HF Type) vs SiNx (LF Type)
U. Zaghloul et al., Nanotechnology 22, 205708, 2011
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 21Microwave & RF 2013
AFM based techniques: Force Distance CurveCharge discharge kinetics PLUS adhesive force
Source: V. Shahin et al. JCS 2005
U. Zaghloul et al., J. Colloid Interface Sci. 358, 2011
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 22Microwave & RF 2013
AFM based techniques: Force Distance CurveEffect of RH and applied bias on Adhesive force
RH combined with applied bias yield higher adhesion forces due
to electrostatic induce meniscus phenomena.
U. Zaghloul et al., J. Colloid Interface Sci. 358, 2011
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 23Microwave & RF 2013
FDC on MEMS
U. Zaghloul et al., J. Colloid Interface Sci. 358, 2011
SO
UR
CE
: M
EM
S f
rom
AM
ICO
M N
OE
20
07
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 24Microwave & RF 2013
Environmental (PACKAGING) conditions:Contaminants on Charge accumulation : surface potential and
relaxation time
Contaminants as C and/or O yields higher surface potential
(charge accumulation) and slower discharging (larger decay time
constants)
U. Zaghloul et al., Nanotechnology 22, 035705, 2011
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 25Microwave & RF 2013
Major Challenges / Limitations
� Dielectric charging in electrostatic actuated devices
� Metal contact degradation (welding, wearing,
contamination,…): in resistive switches
� Thermal induced elasto-plastic phenomena (creep-
fatigue): in membrane under high workload
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 26Microwave & RF 2013
Major Challenges / Limitations
� Dielectric charging in electrostatic actuated devices
� Metal contact degradation (welding, wearing,
contamination,…): in resistive switches
� Thermal induced elasto-plastic phenomena (creep-
fatigue): in membrane under high workload
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 27Microwave & RF 2013
Metal-to -Metal contact physics
Source: A. Broue PhD (LAAS-Fialab - 2012) Grant from: ANR – EDA/DGA – Region MP.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 28Microwave & RF 2013
Micro-contact reliabilityFailure mechanisms
Commonly reported failure mechanisms are:
• Mechanical (cold welding, strain hardening, wear, fretting…)
• Electro-thermal (hot welding, annealing, arcing, creep, softening…)
• Chemical (contaminations, frictional polymers, corrosion, oxidation or sulfidation: formation of insulating films at the extreme surface)
These Mechanisms yield topological, mechanical and/or electricalproperties modifications at the contact
Source: A. Broue PhD (LAAS-Fialab - 2012)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 29Microwave & RF 2013
Micro-contact physics
• The contact resistance Rc is linked to the constriction of current lines
between both contacts � local increase of the current density +
ballistic transport of electrons
Relationship between contact resistance Rc and the load applied Fc on the contact
The highest contact spot temperature Tc expressed as a function of the contact voltage Vc
RC = AFC−x
04
2
TL
VT c
c +=
Electrical contact area
RContact = Γ(K )RHolm + RSharvin +RFilm ?( ) RSharvin = 4ρK3π a
RHolm = ρ2a
where and
The effective contact
area is much smaller
than the apparent one
� due to the small force
available in micro
actuators (50 – 250 μN)
Diffusive
conduction
mode
Ballistic
conduction
mode
Source: A. Broue PhD (LAAS-Fialab – 2012)
Grant from: ANR – EDA/DGA – Region MP.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 30Microwave & RF 2013
Test vehicle description
Au-to-Au Ru-to-Ru Au-to-Ru
++ High bulk conductivity
++ High oxidation resistance
- - Soft material (large modification of
the contact surface, susceptible to
contact wear and stiction)
Au ++ Higher hardness
++ Higher melting temperature
- - Lower bulk conductivity
Ru
Monometallic contacts
Contact materials Au Ru Rh Ni
Electrical conductivity (mΩ-1.mm-2) 45.7 14.9 21,1 14,3
Softening temperature (°C) ~100°C ~430°C x ~520°C
Melting temperature (°C) 1063°C 2450°C 1964°C 1453°C
Boiling temperature (°C) 2966°C 4900°C 3695°C 2837°C
Estimated hardness (GPa) ~1.6 ~10.1 ~25 ~13,7
Rh
Ni
Rh-to-Rh Au-to-Ni
Bimetallic contacts
Source: A. Broue PhD (LAAS-Fialab - 2012)
Source: A. Broue PhD (LAAS-Fialab – 2012)
Grant from: ANR – EDA/DGA – Region MP.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 31Microwave & RF 2013
Description of the experimental set-up
• Specific contact investigation:Source Modes Switching Modes
•Current source or voltage source
Hot switching
Cold switching
Mechanical switching
Input Parameters Range
•Current level (Ic) 10-5 to 1A
•Maximum load applied (Lmax) 1µN to 6mN
•Contact voltage(Uc) 10-5 to 40V
•Holding plateau at load max thold 0 to several min
Environment Dry nitrogen (< 5% RH)
Outputs
•Voltage Drop (Vc) or current drop
(Ic) [depending on the source
mode]
•Contact stiffness (K)
•Tip Displacement (d) •Contact resistance (Rc)
*Contact force resolution = 1µN
displacement resolution = 1nm
*test structures are reported and micro
bonded on a PCB (Printed Circuit Board).
Source: A. Broue PhD (LAAS-Fialab - 2012)
Test Vehicle (4 point)
Grant from: ANR – EDA/DGA – Region MP.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 32Microwave & RF 2013
Contact Characterization
Contact resistance versus contact force at different values of current
A. Broue, et al. IEEE Holm Conference on Electrical Contacts, Charleston (USA), 2010
Au/Au
Rc
R2
F1 Force de contact F2
R1
Couple de matériaux
Grant from: ANR – EDA/DGA – Region MP.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 33Microwave & RF 2013
Metal Contact Characterization
Contact resistance versus contact force at different values of current
A. Broue, Iet al. MEMS 2010, Hong Kong (Chine), 24-28 Janvier 2010
Grant from: ANR – EDA/DGA – Region MP.
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 34Microwave & RF 2013
Metal Contact Characterization
Major failure modes for different metal type vs cycling
Source: F. Ke, et al. Microelectromechanical Systems, Journal of, 2008
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 35Microwave & RF 2013
Major Challenges / Limitations
� Dielectric charging in electrostatic actuated devices
� Metal contact degradation (welding, wearing,
contamination,…): in resistive switches
� Thermal induced elasto-plastic phenomena (creep-
fatigue): in membrane under high workload
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 36Microwave & RF 2013
Major Challenges / Limitations
� Dielectric charging in electrostatic actuated devices
� Metal contact degradation (welding, wearing,
contamination,…): in resistive switches
� Thermaly induced elasto-plastic phenomena (creep-
fatigue, …): in membrane under high workload
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 37Microwave & RF 2013
Free Standing Membrane Physics
Source: Innovation For High Performance
Microelectronics (IHP 2012)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 38Microwave & RF 2013
Thin Membrane Physics
– Co-integration CMOS-MEMS Based on
commercial BiCMOS process
– RF behaviour strongly dependent from
membrane shape in the contact area
Contact Region
UP
stat
eD
OW
Nst
ate
MIM
MIM
Resistive contact (TiN-TiN)
Source: Innovation For High Performance Microelectronics (IHP 2012)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 39Microwave & RF 2013
High TRL environments• Low dispersion
– 6 different versions of the switch are compared
0 10 20 30 40 50 60 70 80 90 100 110 120-25
-20
-15
-10
-5
0
Isol
atio
n (
dB)
Frequency (GHz)
V2 V3 V4 V5 V6
0 10 20 30 40 50 60 70 80 90 100 110 120-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0R
L (d
B)
Frequency (GHz)
V2 V3 V4 V5 V6
0 10 20 30 40 50 60 70 80 90 100 110 120-5.0
-4.5
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
IL (
dB)
Frequency (GHz)
V2 V3 V4 V5 V6
Design and characterization done in IHP
All the switches have the same contact area and inductors are added on the anchors for
frequency tuning
Grant from: ESA – IHP – ThalesAleniaSpace
Source: N. Torres Matabosch PhD 2013 (CNRS-LAAS –ThalesAleniaSpace)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 40Microwave & RF 2013
Effect of Process Dispersion • Fabrication process dispersion
� UP and DOWN capacitance dispersion due to different stress level over the wafer
CMIM
ZMEMS
CM1-M3
Lelectrode
Relectrode
Ranchor
Lanchor
Lbeam
Cox2
Cox1
IN OUTSubstrate
coupling model
16 18 20 22 24 115120125130135140145150
0
2
4
6
8
10
Nu
mb
er
of
de
vic
es
CMEMS(fF)
UP state σUP=1.2fF
DOWN state σDOWN=6.3fF
Precision Impedance
Analyzer 4294A
(@1MHz)
CDOWNCUP
Grant from: ESA – IHP – ThalesAleniaSpace
Source: N. Torres Matabosch PhD 2013 (CNRS-LAAS – TAS)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 41Microwave & RF 2013
• Failure anlaysis– S-Parameters before and after stress
• The resonance is due to the mechanical fatigue of the membrane– UP state: CMEMS and CM1-M3 increase– DOWN state: resistive contact membrane-electrode � not possible to
model
25 30 35 40 45 50 55 60 65 70-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
IL (
dB
)
Frequency (GHz)
16h 1h Initial
20 25 30 35 40 45 50 55 60 65 70-7
-6
-5
-4
-3
-2
-1
0
IL (
dB)
Frequency (GHz)
Model Initial After stress
Working device Failed device
d(M1-M3) d(M2-M3)
Effect of Process Dispersion
Grant from: ESA – IHP – ThalesAleniaSpaceSource: N. Torres Matabosch PhD 2013 (CNRS-LAAS –TAS)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 42Microwave & RF 2013
• Failure analysis– Test plan: 1h constant DC stress
• Industrial requirements (TAS): ∆∆∆∆Vp<10% and ∆∆∆∆IL<1dB
Vpout >36V and |Vpin -Vpout |<1V
0% 10% 20% 30% 40% 50% 60% 70% 80% 90%
100%
21 23 25 27 29 31 33 35 37 39
Dev
iatio
n in
VP
OU
T
VPOUT (V)
Devices that succeeded the tests
Define a failure criteria for wafer screening
Tests done in ThalesAleniaSpace facilities - Toulouse
The diameter of the circles represents the |Vpin -Vpout |
Effect of Process DispersionFailure criteria and identification
T = 22°CRH = 45% (rel. humidity)
Grant from: ESA – IHP – ThalesAleniaSpace
Source: N. Torres Matabosch PhD 2013 (CNRS-LAAS –TAS)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 43Microwave & RF 2013
• Early detection of failed devices– Profilometer-based Measurements � Real time and Non Intrusive– Allow rapid wafer level monitoring (screening)
5 6 7
13
14
15
16
X
Y
Effect of Process Dispersion
180 190 200 210 220 230 240 250 260 2700,0
0,5
1,0
1,5
2,0
2,5
3,0
d(M
2-M
3)
Y (um)
Failed Succeeded
4.7µm
2.8µm
0 50 100 150 200 250 3000123456789
10111213
d(M
1-M
3)
X (um)
Failed Succeeded
Grant from: ESA – IHP – ThalesAleniaSpaceSource: N. Torres Matabosch PhD 2013 (CNRS-LAAS – TAS)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 44Microwave & RF 2013
Conclusions & Perspectives
MEMS switches failure mechanisms are a difficult multiphysics / multidisplinar challenge. Their study by means of “ad-hoc” experimental methodologies such to target phenomena separately, has allowed to advance in the fundamental understanding of the underlying phenomena.
In commercial devices solutions to prevent major FM include:
� Metal-to-Dielectric Charging*: � No contact actuators (dielectricless); � Small CON/COFF ratio
� Material engineering (enhance discharging mechanisms) � Higher Process complexity
� Metal-to-Metal Contact Degradation*:� Hard metals � Lower contact resistance, Higher Process complexity
� Strong forces � Higher actuation bias
� Movable Membrane/Beams Creep and Fatigue:� Thermal stress engineering/compensation � Higher process complexity
� Thicker membranes � Higher actuation bias
* Working environment (e.g. packaging) is essential: inert gasses with low RH contents and low contaminants (hermetic)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 45Microwave & RF 2013
Conclusions & Perspectives
Maturity and Adoption
� CMOS platform are the most suitable solution for consumer mobile electronics
(co-integration of analog and digital electronics/fuctionalities)
� MEMS foundries well suited for pick-and-replace solution (Yet for
niche/smaller market)
� R&D MEMS foundries essential for supporting both (proof of concept and
failure analysis)
R&D OUTLOOK
� New materials and processes (Carbon based) for faster and smaller
MST (NEMS, i.e. mass sensors or SW)
� Advanced physics (e.g. tribology): electric and thermal transport
across atomic scale multiasperity contact;
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 46Microwave & RF 2013
Conclusions & Perspectives
R&D OUTLOOK
� New materials (Carbon based) for faster and smaller MST (NEMS, i.e.
mass sensors or SW)
� surface physics tribology: electric and thermal transport across
atomic scale multiasperity contact;
Source: IBM Reserach Zurich (2013)
F. COCCETTI CNRS-LAAS / Fialab - coccetti@laas.fr 47Microwave & RF 2013
Fostering Education on RF-MSThttp://educ.laas.fr/ISS_RFMEMS2013
top related