micro-electromechanical systems (mems) technology and ......accelerometer – state-of-research...
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Micro-electromechanical Systems (MEMS) Technology and Applications APAC Innovation Summit 2016 Series – Sensors
Professor William C. Tang Microbiomechanics Laboratory Department of Biomedical Engineering Department of Electrical Engineering & Computer Science Department of Chemical Engineering & Materials Science Henry Samueli School of Engineering University of California, Irvine
In the Past 20 Years…
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50K
100K
150K
200K
250K
300K
Annual Publications
Institute of Electrical and Electronics Engineers (IEEE) – World’s largest, 300,000 members in 160 countries – 4m publications since 1884, 3.2m past 20 years alone
1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015
Circuits
5%
10%
15%
20%
25%
30%
Communications
Sensors
% o
f A
ll P
ub
lica
tio
ns
MEMS Advantages: Integration, Miniaturization, & Batch Fabrication
Make IC or MEMS affordable even with a $2B cleanroom
3,140 dies per wafer
25 wafer per batch
78,500 per batch
(a) 20 cm
(b)
3.75 mm
(c)
0.7 mm
(d)
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Source: galleryhip.com
Self-limiting etches
Boron-doped Si membrane
{111}
<100> Slanted {111} Vertical {111}
<110>
Anisotropic Wet Etching of Silicon {100}
{111}
{111}
Backside Mask
Frontside Mask
54.74°
Boron-doped Si membrane
Slanted {111}
109.5°
70.5°
Top View
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Surface Micromachining
Deposit & pattern poly
Poly-Si
Si substrate
Sacrificial etch
Cantilever Anchor
Si substrate
Deposit & pattern oxide
Oxide
Si substrate
10 µm
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1 µm
Deposit Polymer
Polymer(nCF2)
nCFx+
F
Etch
Mask
Silicon
SFx+
Etch
F SFx
+
20 µm
Trenches - Surface Technology Systems
Spring - Klaassen, et al, 1995
Deep Reactive Ion Etching (DRIE)
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Source: N. Maluf
Digital Micromirror Device (DMD) Pixel Size: 16 µm 16 µm Switching Time: < 2 ms
1987 – Invented by L. Hornbeck, TI 2004 – #1 MEMS supplier, 40m DLP shipped to-date 2014 – DLP Cinema in 118,000 theater worldwide,
10m moviegoers per day Other applications – medical, auto, mobile, etc.
TI Digital Light Processor®
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Source: TI.com
Accelerometer – the Beginning
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Displacement sensing (ADXL50)
F m = M a
x
F d = cv Frame
F = kx k Proof mass
Analog Devices ADXL-50: surface-micromachined, integrated BiCMOS
2µm-thick low-stress polysilicon structural layer Integrated BiCMOS capacitive position feedback zeroing BW = 0 Hz to 1.3 KHz; 19 mV/g; +/-50 g full-scale; 6.6mg/Hz noise Overall power consumption = 50mW @ 5V supply
Accelerometer – State-of-Research
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Zhao, et al, “A Sub-µg bias-instability MEMS oscillating accelerometer with an ultra-low-noise read-out circuit in CMOS,” IEEE J. Solid-State Circ., Vol. 50, No. 9, 2015, pp. 2113 – 2126.
60µm-thick SOI structural layer Double-ended tuning fork (DETF) differential resonant stress sensors Continuous-time transimpedance amplifier (TIA) on separate CMOS BW = 0.5 Hz to 350 KHz; 140 Hz/g; +/-20 g full-scale; 2µg/Hz noise Overall power consumption = 3.5mW @ 1.5V supply
Compared to ADXL50 – 270X BW; 3,300X lower noise; 7% of the power; FM output
(111)
R1
R3
Bulk Micromachined Pressure Sensor
Bondpad (100) Si diaphragm
P-type diffused piezoresistor
n-type epitaxial layer
Metal conductors
p-type substrate & frame
Anodically bonded Pyrex substrate
Etched cavity
Backside port
(111)
R2 R1
R3
R2 R1
R4 R3
Vbridge
Vout
Deposit insulator
Diffuse piezoresistors
Deposit & pattern metal
Anisotropic etch of backside cavity
Anodic bonding of glass
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Source: N. Maluf
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Automotive Sensor Applications
Transmission input speed
sensor
Transmission output speed
sensor
Transmission shift position
sensor
Turbo boost sensor
Coolant temperature
sensor
Crankshaft position sensor
Oil temperature sensor
Camshaft position sensor
Transmission temperature
sensor
EGR pressure feedback sensor
Coolant level sensor
Mass air flow sensor
Oxygen sensor
Air cleaner temperature sensor
Manifold absolute pressure sensor
Brake fluid level
sensor
Washer fluid level
sensor
Throttle position sensor
EGR pressure feedback
sensor
EGR Valve position sensor
Knock Sensor
Vehicle height sensor
ABS wheel speed sensor
Accelerator pedal position
sensor
Rear wheel level sensor
Tail light outage sensor
Vehicle speed sensor
Acceleration sensor
Heater core temperature sensor
Air temperature sensor
Ambient air temperature sensor
Barometric pressure sensor
Steering rate sensor
Picture: carcabin
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Automotive Sensor Applications
Knock Sensor
Manifold absolute pressure sensor
EGR Valve position sensor
Tail light outage sensor
Steering rate sensor
Rear wheel level sensor
Air temperature sensor
Vehicle height sensor
ABS wheel speed sensor
Washer fluid level
sensor
Brake fluid level
sensor
Acceleration sensor
Turbo boost sensor
Transmission output speed
sensor
EGR pressure feedback sensor
Coolant temperature
sensor
Vehicle speed sensor
Camshaft position sensor
Transmission shift position
sensor
Transmission temperature
sensor
Oxygen sensor
Coolant level sensor
Oil temperature sensor
Transmission input speed
sensor
Mass air flow sensor
Air cleaner temperature sensor
Barometric pressure sensor
Throttle position sensor
Ambient air temperature sensor
Heater core temperature sensor
Crankshaft position sensor
EGR pressure feedback
sensor
Accelerator pedal position
sensor
Picture: carcabin
0.
10.
20.
30.
40.
50.
60.
70.
80.
90.
100.
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
World Annual Production (million) Cars Commercial vehicles
High volume ~ 90m per year Ultra-rugged High-reliability > 10 years
Statistics: statista.com
Smart Phone Sensor Applications
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Picture: ifixit
Light sensor
Proximity sensor
Finger print sensor
Microphones
Accelerometers and triaxial gyroscopes
Barometer
Smart Phone Sensor Applications
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Picture: ifixit
Light sensor
Proximity sensor
Finger print sensor
Microphones
Accelerometers and triaxial gyroscopes
Barometer
Very high volume ~ 1.5b per year Ultra-miniaturized Mid-reliability ~ 3 years
Source: kingdomtelco
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Biomedical Applications
Annual world healthcare market: $2 trillion $100 billion for medical instruments
$300 billion for pharmaceuticals
$1 billion FDA approval per drug
Annual cost: $3,000 per person
Drive to decentralized medical care Minimize expensive in-patient care
Minimize time consuming lab tests
Shift Point-of-Care (POC) to home by Miniaturizing and lowering costs of
medical instruments
Real-time health monitoring
Automated reliable therapeutic administrations Source: Forbes
Per-Capita Health Expenditure, 2013
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25
26-50
51-100
101-300
301-1,000
No data
N/A
1,001-5,000
>5,000
Health Care Costs vs. Age
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0
0.5
1
1.5
2
2.5
3
0 10 20 30 40 50 60 70
2002 - Male 2002 - Female 2010 - Male 2010 - Female
Source: Health Care Cost Institute Independent Report June 2013 Median age population data: US Census Bureau
Year Median Age (Population)
2010 37.2 (309m)
2000 35.3 (282m)
1990 32.9 (250m)
US
$1,0
00
Source: diehardbrain
Leading Cause of Deaths
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0 100,000 200,000 300,000 400,000 500,000 600,000 700,000
Heart disease: 611,105
Cancer: 584,881
Chronic lower respiratory diseases: 149,205
Accidents (unintentional injuries): 130,557
Stroke (cerebrovascular diseases): 128,978
Alzheimer's disease: 84,767
Diabetes: 75,578
Death in US (2013)
Source: Center for Disease Control and Prevention
Source: USNews
Source: mymodernmed.com
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Application That Need Better Tools
Drug Delivery
Monitoring
Prosthesis
Bio-analyses
Minimally Invasive Surgery
Patches, external and implantable pumps, smart pills
Point-of-care testing, pressure sensing, whole blood analysis
Polymerase chain reaction, genetic tests, electrophoresis, microfluidics
Cochlear implants, retinal implants, neural implants
Cutting tools, smart endoscopes
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In-vitro vs. in-vivo Sensors
In-Vitro
Include clinical chemistry, blood gas/electrolytes, hematology/flow cytometry, coagulation, DNA tests, microbiology, diabetes, urinalysis, and histology/cytology
In-vivo
Include sensing for blood pH, CO2, O2, glucose, acceleration, mechanical stress, drug delivery, cochlear implants, retinal implants, and neural implants
Protein detection on paper substrate (KAIST, 2015)
Biostamps body monitors (UIUC, MC10, 2015)
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DNA Testing
Fastest growing in vitro market segment Far more sensitive than immunoassays or culture
Cancer research Characterization of tumors on a genomic scale
Reliable diagnosis and effective treatment of cancer
Immunology Study of host genomic responses to infections
Individualized therapy Identify genetic predisposition, individual immune
responses, SNP mapping –> personalized drug therapy
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POC Blood Analyses: Abbott i-STAT
Chem/electrolytes: Na, K, Cl, TCO2, Anion Gap, iCa, glucose, Urea nitrogen, Crea, Lactate;
Hematology: Hematocrit, Hemoglobin;
Blood gases: pH, pCO2, HCO3, sO2,
Coagulation: ACT Kaolin, ACT Celite, PT/INR
Endocrinology: β-hCG,
Cardiac Markers: cTnl, CK-MB, BNP
Source: abbottpointofcare.com
Source: turbosquid.com
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Polymer BioMEMS Fabrication
Source: Physics Today, June 2001.
Photomask = transparency film with pattern printed at high resolution (5000 DPI or better)
Photoresist or Su-8 can be used to create “master” or “mold.”
PDMS = poly(dimethylsiloxane), poured over mold.
Fluid inlets/reservoirs drilled into the PDMS.
Flat surface = glass, silicon, PDMS, or plastic.
Printed Circuit Board Microfluidics
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PCB microfluidics for lysing and isotachophoresis
[M. Bachman, GP Li, Integrated Nanosystems Research Facility, UC Irvine]
Nucleic Acid Detection in Droplets
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• Use super-paramagnetic particles (SSP) as substrate for DNA attachment.
• Provide force to move droplets. • Chips primed with buffer droplets for
• Cell lysis • DNA extraction • Purification • Amplification
[J. Wang, Johns Hopkins University, Micro/Nano Fluidics Fundamental Focus Center, UC Irvine]
Paper-Based Microfluidics
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• Less than 1c per assay; sample-to-answer in minutes; truly disposable.
• Light weight, multifunction, easy to manufacture, low power.
• Fundamental: thermodynamics of biochemical reactions in different paper types.
[G. Whitesides, Harvard University, Micro/Nano Fluidics Fundamental Focus Center, UC Irvine]
0 ppb
100 ppb
500 ppb
10 ppm
20 ppm
50 ppm
Reagent “printed” at the tip
Functions of Neural Implants
Extract motor intentions For controlling prosthetic arms, hands, legs
For controlling machines
For controlling computers
Elicit sensations Touch from prosthetic fingerstactile sensors
Vision from camera
Sound from microphone
Suppress unwanted movements E.g., essential tremor, Parkinson, high blood pressure
Suppress unwanted sensations E.g., hunger, pain
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Source: goshenschoolny.org
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Cochlear Implants
Battery Compartment
Processor Module
Headpiece
In-the-ear microphone
28 mm x 56 mm flexible silicone x 5.5 mm
Receiver/transmitter coil: 3-turn gold wire with platinum
helix shielding
Deep Brain Stimulation
For example: Medtronic DBS Therapy: Essential tremor
Parkinson’s disease
Dystonia (not demonstrated yet)
Obsessive-compulsive disorder (not demonstrated yet)
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Source: Medtronic
Conclusions
MEMS sensor technology development driven by
Low-cost, high-volume needs for consumer products
Mid- to-low-cost, medium-to-high-volume applications for healthcare industries
Relevance to megatrends (EY Global 2015)
Digital future
IoT sensor nodes
Health reimagined
POC
Wearable sensors
Micro-implants
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