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ESD Basics
BASIC CONCEPTS IN
ELECTROSTATIC DISCHARGE (ESD)
©Copyright 20１２ DESCO INDUSTRIES INC.
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Introduction
Eric Williams – Desco Asia
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Introduction
DESCO INDUSTRIES INC.
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Presentation Content
• Background to Specifications
• ESD Basics
– Tribocharging & Materials
– Basics to Specifications
– Testing Methods
• Trends in ESD Protection
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Specification Background
ISO 9000:2000
General Quality
Program
ISO/TS 16949:2002
Automotive
ESD Control Program
ANSI/ESD S20.20
IEC 61340-5-1
RCJ-5-1
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Specification Background
JEDEC
JESD625-A:1999
MIL-STD 1686C
1995
ANSI
ESD S20.20-1999
IEC
61340-5-1/TR2:1998
ANSI
ESD S20.20-2007
IEC
61340-5-1:2007
RCJS-5-1:2010
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ANSI/ESD S20.20-2007
IEC 61340-5-1:2007
Content
6.0 & 5.1 ESD Control Program
•6.1 & 5.1.1 ESD Control Plan Requirements
•6.2 & 5.1.2 ESD Control Program Manager or Coordinator
•6.3 & 5.1.3 Tailoring.
7.0 & 5.2 ESD Control Program Admin. Requirements
•7.1 & 5.2.1 ESD Control Program Plan
•7.2 & 5.2.2 Training Plan
•7.3 & 5.2.3 Compliance Verification Plan
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ANSI/ESD S20.20-2007
IEC 61340-5-1:2007
Content
8.0 & 5.3 ESD Control Program Technical Requirements
•8.1 & 5.3.1 Grounding/Equipotential Bonding Systems
•8.2 & 5.3.2 Personnel Grounding
•8.3 & 5.3.3 ESD Protected Areas (EPAs)
•8.4 & 5.3.4 Packaging
•8.5 & 5.3.5 Marking
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ESD Basics
ESD Control Training
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All Materials Tribocharge
ElectroStatic Charge Generation:
• When 2 Surfaces in
Contact then Separate
• Some Atom Electrons Move
Causing Imbalance
One Surface Has Positive
Charge & One Surface Has
Negative Charge
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Field Meter Demonstration
Measurements
– Be Careful of Charge Suppression
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ESD or
ElectroStatic Discharge
• Charges Seek Balance
• Discharge is Rapid
• Creating Heat
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Examples Of Electrostatic
Discharge or ESD
• Lightning
• Zap from a door
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Two Types of
Materials: Conductors
• Electrical Current Flows Easily
• So Can be Grounded
• Can Discharge
• Examples Metals and People
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Two Types of
Materials: Insulators
• Electrical Current Does Not Flow Easily
• So Cannot be Grounded
• Example: Plastics
• Typically very high charging
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Large Charges
Generated All The Time
• Walking across a carpet:
1,500 - 35,000V
• Walking over vinyl floor:
250 - 12,000V
• Vinyl envelope:
600 - 7,000V
• Worker at a bench:
700 - 6,000V
• Unwinding regular tape:
9,000 - 15,000V
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HBM Voltage Demonstration
• HBM Test Kit
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People Discharge
Frequently
But To feel a
Discharge it
must be
about
3,000 volts
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ESD That A Person Can’t Feel
Can Easily Damage Electronic
Comonents
100 volts or
less can
damage
components!
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Device Sensitivity Classes
Human Body Model (HBM)
• ESD Class 0: Cannot Feel
0 to 199V
• ESD Class 1: Cannot Feel
200 to 1,999V
• ESD Class 2: Feel a little
2,000 to 3,999V
• ESD Class 3: Starts to become painful
4,000 to 15,999V
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Electronic Component ESD
Sensitivity (ESDS)
•
•
•
•
•
•
•
•
•
•
•
COMPONENT TYPE
RF-FETS (MICROWAVE)
GMR-HEADS
PENTIUM
V.MOS
MOSFET
EPROM
J.FET
SAW
OP AMP
CMOS
FAILURE LEVELS
1-5V
1-5V
5V
30V
100V
100V
140V
150V
190V
250V
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Tiny Conductive Paths Can
Easily Be Damaged
Smaller components mean greater sensitivity to ESD. Damage
to these components cannot be detected by the naked eye.
•
Integrated Circuit
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Tiny Conductive Paths Can
Easily Be Damaged
• At this
magnification
we see that
1/2 of the
width of the
material
has been
destroyed
•
Integrated Circuit
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Tiny Conductive Paths Can
Easily Be Damaged
• At higher
magnification,
the pit in the
area between
the base and
emitter becomes
more obvious
•
Integrated Circuit
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High Magnification Photos of ESD
Damage
Images of Human Body Model (HBM) ESD damage. Damage
visible using Scanning electron micrograph (SEM) after
significant enhancement by delayering and etch
enhancement.
Used with permission of
Hi-Rel Laboratories, Inc. Spokane WA 99217
www.hrlabs.com
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Photo of ESD arcing from finger to component.
This is not a computer simulation. Technician
was connected to a small magneto.
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This is not HBM-ESD. Extensive damage on this
transistor where the bond has melted is typical of
surges from Inductors, Transformers, and Motors.
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Arcing of this nature within an integrated circuit is typical of
testing damage. Human Body Model ESD does not create
sufficient damage to be seen in an optical microscope.
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Optical photo of a large Integrated Circuit which
has experienced ESD damage to the pin noted by
the arrow.
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Higher magnification photo of pin noted by the arrow in the prior
slide This taken at 400 times magnification on a 4" X 5" photo.
The damage is noted as the "fuzz" at the end of the arrow.
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Now you see it!! Overlying glassifcation has been
removed and the surface decorated to show the ESD
damage at 5,000 times magnification in this scanning
electron micrograph.
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Techniques used to locate HBM-ESD damage in an integrated circuit.
Clockwise from the upper left optical photo at 400X shows no damage. The
upper right hand scanning electron micrograph (SEM) shows no damage. The
lower right hand image is the current flow in the device
which shows a
subsurface arc
between the two
metal lines. The
lower left photo
is a
combination of
the SEM image
and the current
flow image.
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Scanning electron micrograph (SEM) image of the device in
prior slide after glassifcation removal and surface decoration.
The enlargement 2,000 times magnification.
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Optical micrograph of an Integrated Circuit damaged by
HBM ESD. Damage has occurred in the large thin oxide
metal capacitor in the upper center of the image. However,
no physical damage is visible.
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Scanning electron micrograph (SEM) image of the ESD
damage after removal of the capacitor metallization. Note
the characteristic eruption thru the oxide. Magnification is
10,500 times.
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Optical image of an Integrated Circuit damaged by HBM
ESD. The second pin from the bottom left is good and its
mirror image, second from the right is damaged. However,
no physical damage is visible.
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Scanning electron micrograph (SEM image of the damage
site on the Integrated Circuit shown in prior slide. Metal has
been removed expose the underlying damage site.
Magnification is 6,450 times.
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Types Of ESD
Device Damage
• Latent Defect
Component wounded
But Inspection Passes
• Catastrophic Failures
Inspection
Able to detect
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Latent Defects
More Costly
• Sub Assembly passes inspection
• Assembly passes inspection
• Product passes inspection
• Works a while for customer
• Then Upsets & Mysterious Problems
• More Returns
• More Warranty Costs
• Lower Customer Satisfaction
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Like Germs, ESD Is The
Hidden Enemy
Control Germs
We are aware of
sterilization in medicine
Control ESD
We should develop the
same attitude about ESD
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The Prerequisites
of ESD Control
• Identify ESD Area
• Identify ESD sensitive
items
• Provide ESD
control training
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The Basics Of ESD Control
• Ground Conductors
• Shield ESDS When store or
transport outside EPA
• Neutralize insulators with
ionizers
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Ground Conductors
Including People
• Wrist Straps
• Must work, so test wrist
strap daily (or use
continuous monitors)
• Foot Grounders
• Must work, so
test foot grounder daily
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When in the EPA, Ground All
Conductors Including People
• Wrist Strap System Resistance
to Ground
• Footwear System Resistance to
Ground
• <3.5ｘ107Ω
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•Why is it <3.5ｘ107Ω
•ESD TR20.20 Figure 14
•Human Voltage
•120
•100
•80
•60
•40
•20
•0
•1
•10
•20
•40
•Human Resistance To Ground（M Ω ）
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Ground All Conductors in
ESD Protected Area
• Dissipative Work Surfaces
– Ground ESD worksurface via
ground cord to common point
ground to equipment ground
•Conductive Floor Mats
– Ground ESD floor mats via
ground cord to equipment ground
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Resistance Measurements for
ANSI/ESD S20.20
You must Ground People:
If seated you must
• Wrist Band (worn - RTG) :
If standing
• Footwear (RTG):
OR
• Footwear (RTG)
<3.5 x 107Ω
<3.5 x 107Ω
<1.0 x 109Ω and less
than 100 Volts
Generation
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Resistance Measurements for
ANSI/ESD S20.20
Other Optional Items for the EPA:
• Floor (RTG):
<1.0 x 109Ω
• Chair (RTG):
<1.0 x 109Ω
• Garment (RTT):
<1.0 x 1011Ω
(for Static Control)
• Work surface (RTG):
<1.0 x 109Ω
• Storage Rack (RTG):
<1.0 x 109Ω
• Cart or Trolley (RTG) :
<1.0 x 109Ω
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SRM Demonstration
• Surface Resistance Meter
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Neutralize Insulators
Via Ionizers
• Charged Insulators Cannot be grounded
• Ionizer air flow floods area with Ions
- Neutralizing Charge
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Ionizer Demonstration
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Checking Ionizers
ESD TR53-01-06, Page 21
•Decay Time from 1000V to 100V
• 50552 Ionization Test Kit
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Checkng Ionizers
• 50561 Charged Plate Monitor
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Shield ESD Sensitive Items
Outside Protected Area
Faraday Cage
Charges Kept on Outside
of Package:
• Closed Metallized Shielding Bag
• Covered conductive tote box
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Recent Trends in ESD
• Focus on different models
– Focus on the prevention of static
generation and discharge
• Difference between models
• New Tools for Measurement
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Recent Trends
1. Machine Model
General Solution - Grounding Machine and Material:
Check Ground to Surface Resistance, Ionization, Machine
Parts/Component Voltage Measurement.
2. Human Body Model
General Solution - Grounding Human Body:
ESD Safe Floor, ESD Safe Garment, Wrist Strap, Human
Body Voltage Measurement.
3. Charge Device Model
General Solution - Control Device Charge:
ESD Safe Palette, Ionization,
Device Charge Voltage Measurement.
4. Next Control Item: EMI/EMC Control
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What is the difference 100V CDM more
Damaging than 100V HBM?
•
Q=CV
• Coulomb Value
1. Human Body: 100 pF (10 nQ)
2. Charge Device: 1 pF (0.1 nQ)
*LCD Substrate: 200 to 300 pF (20 to 30 nQ)
• Size of object
1. HBM（Human Body: 1.5 to 2 m）
2. CDM（Device: few mm to 1 cm）
* LCD Substrate: 2m X 3m (max)
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What is the difference 100V CDM more
Damaging than 100V HBM?
• Discharging Current
1. 100VHBM（0.06A）
2. 100VCDM（0.90A）
* LCD (more than 10A?)
• Discharge Time
1. HBM（500n sec）
2. CDM（ 1.5n sec）
* LCD (same as CDM)
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Recent Trends
Measurement・Sensing
1. EMI Detectors
EMI Detectors
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Recent Trends
Demonstration
•EMI Detector
•Electrostatic Field Meter Limitations
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ESD Basice
Thank you – 谢谢
©Copyright 2012 DESCO INDUSTRIES INC.
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