1 pressure / stress sensors patrick pons, philippe menini 5 phd, 1 post doc 1 recif engineer...
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1
PRESSURE / STRESS SENSORS
Patrick PONS, Philippe MENINI
5 phD, 1 post doc1 RECIF Engineer
November 2006
INTRODUCTION
Objectives
• Development of silicon membrane pressure sensors for specific applications (automobile, aeronautic, medical)
• Pressure range• Temperature range• Sensitivity / accuracy
• Multisensors integration
• Integration of communication circuits / wireless sensor
• Development of new transduction type
Developments achieved : 1980 2005
• Capacitive transduction : silicon / pyrex
• Piezoresistive transduction : mono and polycristalline silicon gauges
Transduction Probre integration Packaging
Design Technology
3
CAPACITIVE SENSORS
Pyrex
Silicium H H1
H2
L
D
• 20 m < H < H1• 300 m < H1 < 500 m• 0.5 mm < H2 < 1.5 mm• 1.5 m < D < 3 m• 2 mm < L < 4 mm• Chip area : 5 x 5 mm2 to 7 x 7 mm2
Functional characteristicsFunctional characteristics • Pressure range : 0.1 to 100 bars • Nominal capacitance : 10 to 100 pF • Full scale response (FS) : 5 to 15 % • Nonlinearity : ± 1 to ± 3 % FS • TCO : < 100 ppm / °C • TCS : 100 to 2000 ppm / °C • Temperature range : - 40 to 180 °C
Pressure sensor for automobile tire : 0 / 6 bars, - 40 / 120 °C
CAPACITIVE SENSORS – Two linear range Two linear range
0 2 4 6 8 10 12 14 16 1820
30
40
50
60
70
80
90
100
110
Ca
pa
cita
nce
(p
F)
Pressure (bar)
Pressure (bar)
Ca
pa
cita
nce
(p
F)
4,0 4,5 5,0 5,5 6,0 6,5 7,0 7,5
36
37
38
39
40
41
42
43
44
45
Sp = 2.3 pF/barNL = ± 1.7% FS
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0
21,6
21,8
22,0
22,2
22,4
22,6
22,8
23,0
23,2
23,4
23,6
Sp = 2 pF/barNL = ± 1.2% FS
Ca
pa
cita
nce
(p
F)
Pressure (bar)
Mohamad Al Bahri(Oct 2000 / May 2005)
Fouad KerrourMay 2006 / Oct 2007
PhD Univ. Constantine
5
CAPACITIVE SENSORS - Thermal drift in circular cavityThermal drift in circular cavity
-30 0 30 60 90 120 15080
90
100
110
120
130
140
150
160
170
180
190
200
210
220
1234567
ABCDEFG
abcdefg
Electrode thickness = 0,1µm (Al)
TC
[C(0
,T)]
(
pp
m/°
C)
Température (°C)
Electrode thickness = 0,8 µm (Al)
Offset : Offset : α(Pyrex-Alu)
Top view
Bottom view
Sensitivity : Sensitivity : α(Pyrex-Si)
-20 0 20 40 60 80 100 120 140 160
-2600-2400-2200-2000-1800-1600-1400-1200-1000-800-600-400-200
0200400600
h
qv00
Tv
Série P5 ( em= 0,1µm )
TC[Sv(T)] (ppm/°C)
Température (°C)
Membrane thickness (h) : 26 µm to 45 µm
Resonant frequency : Resonant frequency : α(Pyrex-Si)
-20 0 20 40 60 80 100 120 140 160-100
0100200300400500600700800900
1000110012001300140015001600170018001900
1
2
3
4
5
6
7
A
B
C
D
E
F
G
a
b
c
d
e
f
g
h
Tf
qf 00
Série P5,P2, et P1 (Circulaire)
TC[fr(0,T)] (ppm/°C)
Température (°C)
Membrane thickness (h) : 26 µm to 45 µm
-30 0 30 60 90 120 150
-1200-1100-1000-900-800-700-600-500-400-300-200-100
0100200300
TC[Sp]Sv=TC[Sv] -2TC[Co]
TC[Sp]fr=2TC[Co] -2TC[fr]
TC
[Sp(
T)]
(p
pm/°
C)
Temperature (°C)
Mohamad Al Bahri(Oct 2000 / May 2005)
Fouad KerrourMay 2006 / Oct 2007
PhD Univ. Constantine
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PIEZORESISTIVE SENSORS
10 m < H < qq 100 mqq 100 µm < L < qq mm
Chip area : 1 mm2 to several 10 mm2
R3
R2 R1
R4
VaVs
Wheatstone bridge
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛−−+≈
3
3
1
1
4
4
2
2
4
1
R
R
R
R
R
R
R
R
V
V
a
sΔΔΔΔΔ
HSilicon
L
Stress gauges
Functionnal characteristicsFunctionnal characteristics - Pressure range : 0.1 to 100 bars - Bridge resistance : 1 to 3 k - Full scale response (FS) : 0.5 to 3 % Va - Nonlinearity : < ± 1 % FS - Nominal Offset : < 1 % Va - TCO : 5 to 100 ppm / °C - TCS : 1000 to 2500 ppm / °C - Temperature range : - 40 to 125 °C (400°C)
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High temperature sensor for aeronautic applicationHigh temperature sensor for aeronautic application - SOI wafer - Temperature range : - 40 à 400 °C - Pressure range : 0.1 à 10 bars - Offset : 0.1 % de la tension d’alimentation - Sensitivity : 2 mV/V/bar - TCS : 1200 ppm / °C
2001 : Industrial transfer (Auxitrol)Industrial transfer (Auxitrol)
Miniature sensor for medicalMiniature sensor for medical application (intracranial)application (intracranial) - Temperature range : 20 à 45 °C - Pressure range : - 80 à 400 mbars - Offset : 0.1 % de la tension d’alimentation - Sensitivity : 5 µV/V/mbar - TCO : 0.2 mbar / °C
Validation phase (HEMODIA)
PIEZORESISTIVE SENSORS
1.5 mm
Mohamad Al BahriPost doc (Dec 2005 – Dec 2006)
EFFECT OF GAUGE LENGHT (L) AND POSITION ON PIEZORESISTIVE SENSOR SENSITIVITY
180 190 200 210170160150
L = 100
L = 2
L = 80L = 40
L = 60
Membrane position
R/R (%)
X axis (µm)
EFFECT OF NON IDEAL CLAMPED MEMBRANE ON PIEZORESISTIVE SENSOR
Silicon die Silicon membrane
Clamped die Clamped membrane
x
y
Rotation at anchorageClamped die
Clamped membrane
MPa
x - y
X axis (µm)
EFFECT OF NON IDEAL CLAMPED SILICON DIE ON PIEZORESISTIVE SENSOR
Silicone joint
500 µm
Silicon die
Sensor deformation under pressure
Silicone joint deformation No significant effects on sensor sensitivity
Objectives- Sensor miniaturization : local measurement, reduce probe traumatism
Die width < 500µm Membrane thickness 1µm (SOI) Implanted gauge thickness 0.1µm, Gauge width < 1µm
- In situ-autocalibration : eliminate external calibration (reduce infection risks) SOI / Pyrex technology Integration of electrostatic pressure generator Integration of high stability voltage source (INSERM)
- Sensor integration into the probe (stress assembly, bio-compatibility)
- Telemetric output (INSERM) : eliminate external cable
MINIATURE TELEMETRIC PIEZORESISTIVE PESSURE SENSOR WITH IN SITU SELF-CALIBRATION
Framework- ANR project (Dec 06 / Dec 09)
Partners : HEMODIA, INSERM, Toulouse Hospital, Epsilon - Regional project (submitted)- Joint Laboratory with HEMODIA (submitted)
Michal OlszackiOct 2005 / Nov 2008
PhD Lodtz Univ. grant
Cesary MajOct 2005 / Nov 2008
PhD Lodtz Univ grant.
Mohamad Al BahriDec 2006 / Dec 2009
Post doc ANR
Pierre YameogoJanv 2007 / Dec 2009)
PhD CIFRE HEMODIA
Applications : Intracranial and Intravascular pressure sensor
WIRELESS PASSIVE PRESSURE SENSOR
S21
(dB
)
RF transduction : resonance frequency modification of planar resonator
Example of 30GHz resonator Others frequency possible (resonator design) Frequency : Size Very high sensitivity to pressure
P
Mehdi JatlaouiOct 2005 / Dec 2008PhD Tunisia grant
MINC collaboration (Hervé Aubert)
Aerospace Valley project (submitted) : Sept 07 / Sept 10
COLLECTIVE PACKAGING FOR PRESSURE SENSOR
Framework : Auxitrol collaboration (Oct 06 / Oct 09) Jean François Le NéalNov 2006 / Oct 2009
PhD CIFRE AUXITROL Objectives :
- Oil suppression (increase temperature range, reduce drift)- Collective process : reduce costs
Studies - Cap assembly
Pyrex, silicon Anodic bonding, thermocompression, eutectic bonding
- Surface micromaching Polymer sacrificial layers Thick dielectric cap layers
SUPERCRITICAL CO2 FOR MEMS APPLICATION Framework :
- Regional project (Oct 06 / Oct 08)- RECIF collaboration- Joint Laboratory with RECIF ?
Laurent Rabbia – Vincent PerrutRECIF Engineer
Objectives : Use of supercritical CO2 properties (low interfacial tension)- Wet etching of polymer sacrificial layer and C02 drying in the same chamber- Complete micromachining under supercritical state- Surface conditionning with Self Assembled Monolayer into CO2
Applications- MEMS release- Packaging release- Microfluidics
??????Oct 2007 / Sept 2010
PhD CIFRE RECIF ?
15
POSSIBLE NEW PROJECTS
Integration of pressure sensors with chemical sensors (FET gauge)
Stress sensors for buried pipes (Veolia)
Stress sensors for satellite (Astrium / Regional project submitted)- Wireless stress network- MINC collaboration