Download Operational Field Coupled ESD Susceptibility of Magnetic Sensor

Operational Field Coupled ESD
Susceptibility of Magnetic Sensor
IC’s in Automotive Applications
*2014 IEEE International Symposium on Electromagnetic Compatibility, Raleigh, North Carolina
Cyrous Rostamzadeh, Robert Bosch LLC – USA, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
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Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Motivation and Objectives
‰
In this Work
¾ Electrostatic Discharge according to IEC61000-4-2
¾ Human Body Model up to ±20 kV (330 pF , 330 Ω
Discharge Network)
¾ Field Coupled ESD, A Ford Test (1995). Today?
¾ Operational Field Coupled ESD, a Fiat - Chrysler Test
¾ ESD and Integrated Circuits Susceptibilities, a real
possibility, it can happen!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Motivation and Objectives...
¾ Modern Automobile: more than 80 applications rely on
Magnetic Hall-Effect Sensors (Integrated Circuits).
¾ More than 2 Billion Hall-Effect Sensors are
manufactured annually.
¾ Hall-Effect Sensors in Automobiles: Safety, Power
Train, Body Electronics…
¾ Integrated Circuits Future: Shrinking Geometries,
Wire-Bond Material Transitioning from Gold to
Copper (15 μm)
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
It is important to know…ESD
is one of the most important
Reliability problems in the
“Integrated Circuit” Industry.
~ 50% of all “Field Failures”
are due to ESD. It cannot be
ignored!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Automotive World
Field Coupled ESD
History
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Field Coupled ESD
December 1994,
Ford Principal EMC Technical Specialist, Mr. Arnie Nielsen
investigated an anomaly, a bizarre behavior in a vehicle…
Difficult to remember, most likely it was Lincoln Town Car.
The result of his research: it was an Electrostatic Discharge event,
not accounted for in component-level EMC specifications. Not just
like a normal ESD event, something different…
or more accurately, it was “Field Coupled ESD” phenomena.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
February 1995:
Ford EMC investigated and developed a:
Magnetic-Field ESD Test Method for
EMC Component-Level Test Requirements.
Key-Tek (Manufacturer of ESD Gun for HBM)
Developed a fixture (attached to ESD Gun for H-Field
ESD Immunity test.
It became part of Ford EMC Validation Requirements
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
FT-12
H-Field
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
OEM EMC Specifications are Revised Continuously
to Address Modern Vehicle Environment.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
October 2006,
Daimler-Chrysler Supplier EMC day at Chrysler
Auburn Hills – Update to the latest EMC Specifications:
Mr. Terry North, EMC Technical Fellow:
“We have observed Electronic Module Malfunctions
due to “Indirect ESD Event”
As a Result, we require an additional
Component-Level Test, it is called:
“Field Coupled ESD Test” I describe today the Test Setup”
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Chrysler-Fiat Operating "Direct Coupled ESD”
CS11979 April 2010
ISO 10605
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Chrysler-Fiat Operating "Field-Coupled ESD”
2 X 470 kΩ Resistors
CS11979 April 2010
ISO 10605
Discharge Islands
Field Coupled Plane
5 = DUT, 6 = DUT Harness, Wiring, 11 = DUT Local Ground, 2 = Filed Coupling Strip, 7 = Battery, 8 = Peripheral and Support Equipment
9 = AN, 16 = Production intent Switches and Sensors, 4 = Isolation Block, 15 = ESD Generator Main Unit
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Chrysler-Fiat Operating "Field-Coupled ESD”
CS11979 April 2010
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Chrysler-Fiat Operating "Field-Coupled ESD”
CS11979 April 2010
ISO 10605
Field Coupled Plane
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
OEM ESD Test Specifications
¾GM3097 (April 2012)
¾Ford EMC_CS_2009 (September 2009)
¾Chrysler CS-11979 (April 2010)
ISO 10605 (2001) & IEC 61000-4-2 Standards with some Modifications.
o
¾Ambient Temperature: 23 +/- 3 C
¾Relative Humidity 20 to 40%
¾Prefer 20oC and 30% RH.
¾Contact Rise Time: tr < 1 ns
¾Air Discharge Rise Time: tr < 20 ns.
¾Discharge Networks: 150 pF/2 kΩ and 330 pF/2 kΩ
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Typically OEM Requires:
ESD Handling Unpowered
ESD Powered, Remote Input/Output
Examples…
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
CI 280 Handling Unpowered
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
7.1 Handling Unpowered
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
3.6.5 Handling Unpowered
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Magnetic Sensor
Integrated Circuits
in Automotive
Applications
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Modern Automobile & Hall Effect Sensor Applications
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Automotive DC Motor with Hall-Effect Sensor Schematic
C1
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Hall-Effect Sensor IC
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Test Setup
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Pre-Field-Coupled ESD Hall-Sensor Output
Hall Sensor Output (Horizontal 5 sec/div.
Vertical 10 Volt/div), 100 Hz.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Post-Field-Coupled ESD (±15 KV)Hall-Sensor Output
Hall Sensor Output (Horizontal 5 sec/div.
Vertical 10 Volt/div). 100 Hz
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
At (±20 KV Field-Coupled ESD)
Complete Loss of Hall-Sensor Output Signal!
Corrupted Sensor Output Signal Starts
@ ±15 KV, incrementing at 1KV above ±15 KV -
Output Signal Degrades Gradually,
Worsens - Resulting in a large DC Offset
Voltage.
Finally, Complete Loss of Signal @ ±20 KV.
Resulting in Permanent Damage to Device.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Monitoring Field Coupled to DUT
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Magnetic Field Coupling
Magnetic Field Coupling, Horizontal scale: 5ns/div, Vertical
scale: 500mV/div
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Pre-ESD, Post-ESD
Impedance Characteristics
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Impedance Characterization
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Impedance Characterization
C1
10 nF MLCC
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Pre-ESD, Post-ESD
Hall-Sensor IC
Imaging Inspection
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Pre-ESD Hall Effect Sensor IC
Post-ESD Bond-Wire Defect
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD
Observations
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
We can ESD see in action!
ESD when applied to 0603 MLCC (Multi-Layer
Ceramic Capacitor - X7R)
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Causes Physical Damage, you can see it!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Causes Permanent Damage!
When you look at its Electrical Characteristics
Pre-ESD, Post-ESD
600 Ω
“R” Behavior
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
A Discharge Voltage < 3500 Volts
Cannot be felt by the person involved.
Semiconductor devices fail at 100’s of
Volts!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Impact…
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
IC’s fail due to Excessive Voltage or Energy
Excessive Voltage can cause
Dielectric Breakdown in IC’s
such as Oxide Barriers.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Excessive Energy can cause Thermal Failure
by “Melting Silicon” or “Metallization” of IC.
¾ Melting Temperature of Silicon ~ 1,4200C
¾ Melting Temperature of Metallization ~ 6000C
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Voltages as high as
30 kV has been
observed in automotive
environment.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD is rich in HighFrequency (> 3 GHz)!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD event can create
Currents in Excess of
30 Amps!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD currents can
destroy IC’s, PCB traces
and other Components !
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD can create timevarying Magnetic Field:
25 Amp/m
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD can create timevarying Electric Field
as high as 10 kV/m
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD can create
Susceptibility Problems.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD phenomena involves Electrical & Thermal Transports on
the Scale of nanometers (nm), Circuits and Electronics on the
Scale of micrometers (μm), Semiconductor Chip designs
range from picoseconds (ps) to microseconds (μs), Electrical
Currents of interest range from mA to 10’s of Amperes.
Voltages range from Volts to kiloVolts (kV). Temperatures vary
from room temperature to melting temperatures of 1000’s
0K…
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Must Quantify the Scale in Space & Time
ESD phenomena involves:
Microscopic to Macroscopic Scales.
¾ESD is a Thermo-Electric Transport of Material
Physics
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body ESD
HBM
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Capacitance – ESD
Charge Storage Element
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Charge Storage Capacitance
4πε
C=
⎛1 1⎞
⎜⎜ − ⎟⎟
⎝ r1 r2 ⎠
r1
r2
if r2 ⇒ ∞, and for free space, ε = 8.85 × 10−12 F / m
C = (111 × r ) pF, a human has a surface area ≈ to 1 meter
diameter sphere, ⇒ C Human Body ≈ 50 pF
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Starting with
Guass’s Law
v v
∫∫ D ⋅ ds = ∫∫∫ ρdv = Q,
v
v
v
v
D = εE = ε 0ε r E
s
v v
v
v
2
∫∫ E ⋅ ds = 4πε 0 r E = Q, E =
s
Q
4πε 0 r
2
r̂
v v
Q ⎡1 1 ⎤
V = − ∫ E ⋅ dr =
⎢ − ⎥ → Q = CV ,
4πε ⎣ r1 r2 ⎦
r1
4πε
C=
⎛1⎞ ⎛1⎞
⎜⎜ ⎟⎟ − ⎜⎜ ⎟⎟
⎝ r1 ⎠ ⎝ r2 ⎠
r2
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Free-Space Capacitance
Human Body Capacitance
Earth’s Capacitance
An object a size of marble
50 pF
700 μF
1 pF
¾In addition, we must consider Parallel Plate
Capacitance due to the proximity of an object
to the surrounding
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Self-Capacitance
50 pF
25 kV
NP
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Model (HBM)
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Energy Storage…
The human body is an Electrical Conductor,
full of Salty Fluids. Like any Conductor, the
human body has a Capacitance,
i.e., it stores Electrical Energy,
with respect to its surroundings, such as the
floor, the walls, or other people…
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Energy Storage…
a person's Capacitance is one of his or her
body's attributes. Human attributes can be
affected by the surroundings.
…a person's Capacitance depends on
many factors, including it's Posture, its
Relative Position, and its Proximity to
other Electrically Conducting Objects.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Model (HBM)
¾Therefore, the Capacitance of a Human Body is
the Combination of Free-Space Capacitance +
Parallel-Plate Capacitance and can vary from
50 pF to 250 pF
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Model (HBM)
VHB
C HB = 50 − 250 pF
RHB = 500 Ω − 10 kΩ
VHB = 0 to 25 kV
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Model (HBM)
For a Human Body of 100 pF Capacitance, Charged Up
to 25 kVolt, Energy Released Per Discharge…….
1
1
2
−12
2
Energy = CV = ×100 ×10 × (25,000)
2
2
Energy ≈ 30 mJ
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Human Body Model (HBM)
The Discharge of a Human (via a small,
hand-held metal piece) is basis for the
current waveform most often used IEC
61000-4-2 standard.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Mathematical Analysis
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
n
n
⎛ t ⎞
⎛t ⎞
⎜⎜ ⎟⎟
⎜⎜ ⎟⎟
τ3 ⎠
τ1 ⎠
⎛ −t ⎞
⎛ − t ⎞ i2
i1
⎝
⎝
i (t ) = •
• exp⎜⎜ ⎟⎟
• exp⎜⎜ ⎟⎟ + •
n
n
k1
⎛t ⎞
⎛ t ⎞
⎝ τ4 ⎠
⎝ τ 2 ⎠ k2
1 + ⎜⎜ ⎟⎟
1 + ⎜⎜ ⎟⎟
⎝ τ1 ⎠
⎝τ3 ⎠
⎛ τ ⎛ nτ ⎞1/ n ⎞
k1 = exp⎜ − 1 ⎜⎜ 2 ⎟⎟ ⎟ ,
⎜ τ 2 ⎝ τ1 ⎠ ⎟
⎝
⎠
⎛ τ ⎛ nτ ⎞1/ n ⎞
k 2 = exp⎜ − 3 ⎜⎜ 4 ⎟⎟ ⎟
⎜ τ4 ⎝ τ3 ⎠ ⎟
⎝
⎠
I1 = 21.9 Amp
τ1 = 1.3 ns
τ3 = 6 ns
I2 = 10.1 Amp
τ2 = 1.7 ns
τ4 = 58 ns
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
n=3
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
HBM ESD Time Constant
τ HB = RHBCHB
τ HB = 1500 Ω × 100 pF = 150 ns
9Similar to Thermal Diffusion Time of many
materials used in semiconductor industry
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
9ESD is a Non-Linear Electro-Thermal Physical Event.
9Very Difficult to Model Accurately.
9Simple Linear Model is insightful.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Modeling…
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Generator Model
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Generator Model
VGen = 8 kV
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD HBM Model
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
VHBM = 25 kV
ESD HBM Model • VHBM = 25 kV
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Protection Schemes
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Protection Devices
1. TVS (Transient Voltage Suppressor)
2. MOV Multilayer Zinc Oxide
3. Diode
4. Capacitor
5. Spark Gap
6. Filters
7. Ferrites
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Strategies
¾Avoid Direct Connection from an exposed external
point to an Integrated Circuit.
“E ~ 30 mJ”
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Strategies
In no case should there be a direct
connection from an Integrated Circuit
to an exposed external point.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Strategies
Divert or limit the ESD Energy away
from Circuit Inputs using Filters or
Transient Suppressors.
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Capacitor Mounting Strategy
• How far from Connector Pin…
• PCB layer stack up…
• Y-Connection…
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD Strategies
Solution
IC absorbs a small % of ESD Current!
IHF
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
ESD
Frequency ~ 3 GHz
“Fast Transient Electromagnetics”
Field Collapses to 25 - 40 V within “50 ps – 5 ns”
Structure “Electrically Large”
l>λ
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
High Frequency Design Practice Æ ESD
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Conclusion
¾Potential Destructive Damage to Integrated Circuit due
to Field Coupled ESD may occur. The failure mechanism
was investigated and explored.
¾Coupling Fields may induce device latch-up.
¾Miniaturization, die-shrink and Transitioning bond-wire
Material (from Gold to Nickel – Palladium, Copper) may
introduce immunity concerns which may have not existed
for older generation devices.
¾Field Coupled ESD appears to be a good (critical) test,
correlating well to real-world scenarios. Further OEM
(Ford, GM) research is needed!
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014
Thank you for your
Participation
Cyrous Rostamzadeh, Senior IEEE Member, October 16, 2014