Dragonchip ESD User manual

The Prevention and Control of Electrostatic Discharge (ESD)
AppNote082
Rev1.1
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The Prevention and Control of
Electrostatic Discharge (ESD)
AppNote082
Document Revision 1.1 February, 2018
Dragonchip

The Prevention and Control of Electrostatic Discharge (ESD)
AppNote082
Rev1.1
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Table of Content
1INTRODUCTION TO ESD................................................................................................ 3
2PREVENTION AND CONTROL....................................................................................... 4
2.1 SOURCES OF STATIC ELECTRICITY ...................................................................................... 4
2.2 INDUSTRIAL STANDARD...................................................................................................... 4
2.3 DAMAGE IN AN ELECTRONIC DEVICE.................................................................................... 5
2.4 SCOPE OF AREA IN FACTORY .............................................................................................. 5
2.5 ESD CONTROL DIAGRAM................................................................................................... 6
2.6 PRACTICE SAMPLE............................................................................................................. 6
2.7 ESD MEASURING EQUIPMENT............................................................................................ 7
2.8 ESD TEST METHOD -1...................................................................................................... 7
2.9 ESDTEST METHOD -2...................................................................................................... 8
2.10 ESD CHECK FREQUENCY &CRITERIA .............................................................................. 8
3MACHINE HANDLER FOR PROGRAMMING................................................................. 9
REVISION HISTORY .............................................................................................................. 12

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1 Introduction to ESD
We experience occurrences of static electricity every day.
Example:
Walking along a carpeted floor in a heated room during winter
Electrostatic discharge sensitive (ESDS) parts are commonly characterized to
three defined models:
Human Body Model (HBM)
Machine Model (MM)
Charged Device Model (CDM)
Could damage electronic devices!!!

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2 Prevention and Control
2.1 Sources of static electricity
Object or process
Material or activity
Work surfaces
Waxed, painted or plastic surfaces
Floors
Waxed, common vinyl tiles, sealed concrete
Clothes
Common smocks, non-conductive shoes, synthetic
materials (e.g. nylon)
Chairs
Vinyl, fiber-glass, finished wood
Packaging
Common plastic bags, foam, trays, tote boxes
Assembly area
Spray cleaners, heat guns, blowers, plastic tools
(e.g. solder suckers, brushes),
cathode ray tubes.
2.2 Industrial Standard
MIL-STD-1686C, with HBM subgroups per ESD STM5.1-2001
ESD Model
ESD Classification
Voltage Range
Human Body Model
(HBM)
0
1A
1B
1C
2
3A
3B
0 –249V
250 –499V
500 –999V
1000 –1999V
2000 –3999V
4000 –7999V
>= 8000V
Machine Model (MM)
M1
M2
M3
M4
M5
0 –100V
101 -200V
201 –400V
401 –800V
>800V

The Prevention and Control of Electrostatic Discharge (ESD)
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Charged Device Model
(CDM)
C1
C2
C3
C4
C5
C6
C7
0 –124V
125 –249V
250 –499V
500 –999V
1000 –1499V
1500 –2999V
>= 3000V
2.3 Damage in an electronic device
Two kinds of damage from ESD:
1. Catastrophic damage
1.1. Electronic device is rendered inoperable immediately after the ESD
event.
1.2. A semiconductor junction or a connecting metallization could have been
damaged by ESD.
2. Latent damage
2.1. Electronic device appears to be working fine following the ESD event.
2.2. The sensitive circuitry could be damaged and fail to operate at some time
in the future
2.4 Scope of area in factory
Five areas should we pay attention to:
1. Assembly
2. Test
3. Lab
4. Packing
5. Storage

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2.5 ESD Control Diagram
2.6 Practice Sample
Equipment
Grounding
(0)
Table
Grounding
(1M)
Self grounding
(0)

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2.7 ESD Measuring Equipment
2.8 ESD Test Method - 1

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2.9 ESD Test Method - 2
2.10 ESD Check Frequency & Criteria
Monitor Data + QA Audit

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3 Machine handler for programming
Friction between movable parts, no matter conductive or not, can generate
ESD continuously while moving.
An effective grounding path is an earth wire (yellow/green, or black) between
movable conductive parts as shown below.
Below diagram illustrates the grounding path on a handler of a machine.
A handler consists of test probes mounting on a conductive part with insulator
separated, which then mounting on one end of a hydraulic cylinder and keeps
moving up and down. Even though all parts are conductive, but the contact in
between is not perfect after some days of consumption. Friction between the
cylinder and the rod generates the charges and induces on the test probe. To
minimize the ESD, a grounding path is jointed from the conductive part in the
handler to metal framework which is then jointed to the earth.

The Prevention and Control of Electrostatic Discharge (ESD)
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Hydraulic cylinder
Machine metal framework
(conductive)
Moveable conductive part
Up and down
Connect to ground
Programming pins

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Grounding example:
If the reading of resistance measurement keeps changing between conductive
materials while static or moving, it is an indication that the contact is not stable,
and a new grounding path should be installed.
Conductive part
Joint a wire to the ground

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Revision History
Document
Rev. No.
Issued
Date
Section
Page
Description
Edited By
Reviewed
By
1.1
Jan,
2018
All
Changed to word
Danny Ho
Patrick Li
3
Add machine handler grounding for
programming

The Prevention and Control of Electrostatic Discharge (ESD)
AppNote082
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Copyright Notice
This specification is copyrighted by Dragonchip Ltd. No part of this
specification may be reproduced in any form or means, without the expressed
written consent Dragonchip Ltd.
Disclaimer
Dragonchip Ltd. assumes no responsibility for any errors contained herein.
Copyright by Dragonchip Ltd. All Rights Reserved.
Dragonchip Ltd.
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