IEC TS 61340-5-6:2025

Electrostatics - Part 5-6: Protection of electronic devices from electrostatic phenomena - Process assessment techniques

IEC TS 61340-5-6:2025 establishes a set of methodologies, techniques, and instruments to characterize a process where electrostatic discharge (ESD) sensitive items (ESDS) are handled. ESD risk assessment covers risks by charged personnel, ungrounded conductors, charged ESDS, charged insulators, and ESDS in an electrostatic field. This document applies to activities that manufacture, process, assemble, install, package, label, service, test, inspect, transport, or otherwise handle electrical or electronic parts, assemblies, and equipment susceptible to damage by electrostatic discharges. This document does not apply to electrically initiated explosive items, flammable gases and liquids or powders. The document does not address program management, compliance verification or program manager/coordinator certification. Risks due to electromagnetic sources that produce AC fields are not considered. This document cancels and replaces IEC PAS 61340-5-6 published in 2022. This first edition constitutes a technical revision.

General Information

• Status: Published
• Publication Date: 21-Jul-2025
• ICS: 17.220.99 - Other standards related to electricity and magnetism
• ICS: 29.020 - Electrical engineering in general
• Technical Committee: TC 101 - Electrostatics
• Drafting Committee: WG 5 - TC 101/WG 5
• Current Stage: PPUB - Publication issued
• Start Date: 22-Jul-2025
• Completion Date: 08-Aug-2025

Relations

• Revises: IEC PAS 61340-5-6:2022 - Electrostatics - Part 5-6 : Protection of electronic devices from electrostatic phenomena - Process assessment techniques
• Effective Date: 26-Oct-2025

Overview

IEC TS 61340-5-6:2025 - "Electrostatics - Part 5-6: Protection of electronic devices from electrostatic phenomena - Process assessment techniques" is a Technical Specification from IEC that defines methodologies, measurement techniques and instruments to characterize processes where electrostatic discharge (ESD) sensitive items (ESDS) are handled. This first edition (2025) cancels and replaces IEC PAS 61340-5-6 (2022) and provides a technical revision focused on practical ESD risk assessment for manufacturing and handling operations.

Key topics and requirements

The document centers on practical, instrumented assessment of ESD risk rather than program management or certification. Major technical topics include:

• Measurement techniques for ESD risk assessment (field meters, contact and non‑contact voltmeters, charged plate monitors, Faraday pails, current probes, event detectors, oscilloscopes).
• Sources of ESD risk: charged personnel, ungrounded conductors, charged ESDS, charged insulators, and ESDS exposed to electrostatic fields.
• ESD robustness of devices and assemblies: considerations for Human Body Model (HBM), Charged Device Model (CDM), and discharge of charged conductors and personnel.
• Risk assessment flows for typical process elements: manual handling steps, conductors, charged devices, process‑essential insulators and event detection methods.
• Measurement and instrumentation guidance in informative annexes: grounding tests, contact resistance under ESD conditions, electrostatic field and charge measurement, discharge current measurements, and automated handling equipment grounding.
• Practical examples and preparation: best practices, pick‑and‑place example, and guidance for defining parameter limits.

Note: the specification does not cover electrically initiated explosive devices, flammable materials, program management, compliance verification, program manager certification, or risks from AC electromagnetic fields.

Applications and users

IEC TS 61340-5-6:2025 is intended for personnel who need to assess and mitigate ESD risk in processes that manufacture, assemble, install, package, label, service, test, inspect, transport or otherwise handle electronic parts, assemblies and equipment. Typical users:

• ESD engineers and technicians
• Process and manufacturing engineers
• Test and quality assurance teams
• Facilities and automation engineers (grounding of automated handling equipment)
• Third‑party test labs conducting process characterization

Practical uses include on‑floor ESD risk characterization, selection and verification of measurement instruments, and deriving process‑specific mitigation strategies based on measured charge, voltage and discharge currents.

Related standards

• Replaces IEC PAS 61340-5-6 (2022).
• Part of the broader IEC 61340 electrostatics family (other parts address ESD control program requirements and product test methods). Consult IEC for the latest linked publications and normative references.

Keywords: IEC TS 61340-5-6, electrostatics, ESD risk assessment, electrostatic discharge, ESDS, process assessment techniques, grounding, HBM, CDM, measurement techniques.

Standards Content (Sample)

IEC TS 61340-5-6 ®
Edition 1.0 2025-07
TECHNICAL
SPECIFICATION
Electrostatics -
Part 5-6: Protection of electronic devices from electrostatic phenomena -
Process assessment techniques
ICS 17.220.99; 29.020 ISBN 978-2-8327-0565-0
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CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, symbols and abbreviated terms . 7
3.1 Terms and definitions. 8
3.2 Symbols and abbreviated terms . 8
3.2.1 Symbols . 8
3.2.2 Abbreviated terms . 10
4 Personnel safety . 10
5 Experience level required . 10
6 Measurement techniques for ESD risk assessment . 11
7 ESD robustness of ESDS used in processes . 13
7.1 General considerations . 13
7.2 ESD withstand currents of single devices (components). 13
7.2.1 Human body model . 13
7.2.2 Discharge of charged conductors . 14
7.2.3 Charged device model . 14
7.3 ESD withstand currents of electronic assemblies . 16
7.3.1 Discharge of charged personnel . 16
7.3.2 Discharge of charged conductors . 16
7.3.3 Discharge of boards/systems . 16
7.4 Voltage sensitive devices . 17
8 ESD risk assessment flows . 17
8.1 General considerations . 17
8.2 Manual handling steps . 18
8.2.1 General considerations . 18
8.2.2 Parameter limits for ESD risk assessment in manual handling steps . 18
8.2.3 Detailed ESD risk assessment flow . 19
8.3 Conductors . 21
8.3.1 General considerations . 21
8.3.2 Parameter limits for ESD risk assessment of conductors . 22
8.3.3 Detailed ESD risk assessment flow . 22
8.4 Charged ESDS . 24
8.4.1 General considerations . 24
8.4.2 Parameter limits for ESD risk assessment of charged ESDS . 24
8.4.3 Detailed ESD risk assessment flow . 25
8.5 Risks due to process essential insulators . 27
8.5.1 General considerations . 27
8.5.2 Parameter limits for ESD risk assessment of process essential

insulators . 27
8.5.3 Detailed ESD risk assessment flow . 28
8.6 ESD risk assessment by ESD event detection . 30
8.6.1 General considerations . 30
8.6.2 General procedure . 31
8.6.3 Detailed ESD risk assessment flow . 31
Annex A (informative) Measurement techniques and equipment. 33
A.1 General considerations . 33
A.2 Measurements of grounding . 33
A.2.1 Resistance measurement apparatus . 33
A.2.2 Low resistance meter (DC ohmmeter, multimeter). 35
A.2.3 AC voltage check . 36
A.3 Measurements of contact resistance . 37
A.3.1 Background information and application to ESD risk assessment . 37
A.3.2 Surface, point to point or volume resistance measurements at 10 V and
100 V . 37
A.3.3 Surface, point to point or volume resistance measurements at voltages
greater than 100 V . 38
A.3.4 Determination of contact resistance under ESD conditions . 39
A.4 Measurements of electrostatic fields . 41
A.4.1 General considerations . 41
A.4.2 Electrostatic field meter . 41
A.5 Measurements of charges . 42
A.5.1 General considerations . 42
A.5.2 Faraday pail . 43
A.5.3 Electrometer . 43
A.5.4 Current probe or CDM discharge head or Pellegrini target . 44
A.6 Measurements of electrostatic voltages . 44
A.6.1 Charged plate monitor . 44
A.6.2 Walking test kit . 45
A.6.3 Non-contacting electrostatic voltmeter (ESVM) . 46
A.6.4 Contact voltmeter . 47
A.7 Measurements of discharge events . 48
A.7.1 Antenna with oscilloscope . 48
A.7.2 ESD event detectors . 50
A.8 Measurements of discharge currents . 50
A.8.1 General considerations . 50
A.8.2 Current probe . 51
A.8.3 Pellegrini target . 53
A.8.4 CDM test head . 54
Annex B (informative) Grounding of automated handling equipment (AHE) . 56
B.1 Background information . 56
B.2 Test equipment . 56
B.3 Test procedure. 57
B.4 Suggested equipment grounding guidelines . 57
Annex C (informative) Preparation: What is necessary to prepare an effective ESD
risk assessment? . 59
C.1 Best practices . 59
C.2 Measurement of temperature, humidity and basic electrostatic conditions . 59
C.3 Further hints for preparation . 59
Annex D (informative) ESD risk assessment and mitigation . 60
Annex E (informative) Examples for defining limits in ESD risk assessment for risks
due to charged personnel . 61
Annex F (informative) Example for ESD risk assessment in a "pick and place" process . 63
F.1 Process description . 63
F.2 Parameter limits and equipment . 64
F.3 ESD risk assessment of "Pick operation" . 64
Bibliography . 66

Figure 1 – Direct (best correlation) and indirect (least correlation) measurements to
assess an ESD risk . 12
Figure 2 – Flow to assess ESD risk induced by personnel . 21
Figure 3 – Flow to assess the ESD risk induced by conductors . 24
Figure 4 – Flow to assess the ESD risk induced by charged ESDS . 26
Figure 5 – Flow to assess the ESD risk induced by process essential insulators . 30
Figure 6 – Flow to assess the ESD risk by detecting the electromagnetic radiation
using ESD event detectors or antennas and oscilloscopes . 32
Figure A.1 – Circuit diagram of experiments and simulations of contact resistance . 39
Figure A.2 – Examples of current probes . 52
Figure A.3 – Example of a 4-GHz Pellegrini target . 53
Figure A.4 – Commercially available CDM test head used for discharge current
measurements . 54
Figure E.1 – Discharge current measured in the field and during device qualification
[17] . 61
Figure F.1 – Schematic representation of a "pick and place" operation with two
handlers . 63

Table 1 – Resistance ranges of materials used in this document. 11
Table 2 – Overview of possible instruments used for different scenarios to assess ESD
risk . 12
Table A.1 – Peak current ranges of CDM discharges of small and large verification
modules for oscilloscopes with a bandwidth of 1 GHz and 6 GHz according to
ANSI/ESDA/JEDEC JS-002-2022 [28] . 55

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Electrostatics -
Part 5-6: Protection of electronic devices from electrostatic phenomena –
Process assessment techniques
FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC TS 61340-5-6 has been prepared by IEC technical committee 101: Electrostatics. It is a
Technical Specification.
This Technical Specification cancels and replaces IEC PAS 61340-5-6 published in 2022. This
first edition constitutes a technical revision.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
101/734/DTS 101/741/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 61340 series, published under the general title Electrostatics, can
be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION
This document describes a set of methodologies, techniques, and tools that can be used to
characterize a process where ESD sensitive items (ESDS) are handled. This document's
procedures are meant to be used by those possessing knowledge and experience with
electrostatic measurements.
This document provides methods to determine the level of ESD risk that remains in the process
after ESD control items and materials are implemented.
These test methods' objective is to identify if possibly damaging ESD events are occurring or if
significant electrostatic charges are generated on people, equipment, materials, components,
or printed circuit board assemblies (PCBA) even though there are ESD control precautions in
place.
Sensitivities of ESDS are characterized by industry standard ESD testing and rated by their
withstand voltages or withstand currents. This document is intended to provide methods to
determine whether items of a given withstand voltage or withstand current are at risk in the
process.
The wide variety of ESD control items and materials and the environment in which these items
are used can require test setups different from those described in this document. Users of this
document can adapt the test procedure and setups described in Annex A to produce meaningful
data for the user's application.
Organizations performing these tests can determine if on-going process characterization is
necessary, and if so, the time interval between observations. These observations can also be
made when new products are introduced or when process changes occur. Examples of process
changes include tools, fixtures, equipment, new items/products, and additional manufacturing
steps.
The topics below are not addressed in this document:
– Program management: see IEC 61340-5-1.
– Compliance verification: see IEC TS 61340-5-4 [1] .

___________
Numbers in square brackets refer to the Bibliography.
1 Scope
This part of IEC 61340 establishes a set of methodologies, techniques, and instruments to
characterize a process where electrostatic discharge (ESD) sensitive items (ESDS) are handled.
ESD risk assessment covers risks by charged personnel, ungrounded conductors, charged
ESDS, charged insulators, and ESDS in an electrostatic field.
This document applies to activities that manufacture, process, assemble, install, package, label,
service, test, inspect, transport, or otherwise handle electrical or electronic parts, assemblies,
and equipment susceptible to damage by electrostatic discharges.
This document does not apply to electrically initiated explosive items, flammable gases and
liquids or powders.
The document does not address program management, compliance verification or program
manager/coordinator certification.
Risks due to electromagnetic sources that produce AC fields are not considered.
Descriptions of measurement techniques are given in Annex A.
Annex B provides best practices for grounding automated handling equipment (AHE), Annex C
summarizes the best practices to prepare an effective ESD risk assessment, and Annex D
introduces mitigation measures resulting from the ESD process assessment.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61010-1, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 1: General requirements
IEC 61340-2-3, Electrostatics – Part 2-3: Methods of test for determining the resistance and
resistivity of solid materials used to avoid electrostatic charge accumulation
IEC 61010-2-030, Safety requirements for electrical equipment for measurement, control, and
laboratory use – Part 2-030: Particular requirements for equipment having testing or measuring
circuits
IEC 61340-5-1, Electrostatics – Part 5-1: Protection of electronic devices from electrostatic
phenomena – General requirements
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the terms and definitions given in IEC 61010-1,
IEC 61010-2-030, IEC 61340-5-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
– IEC Electropedia: available at http://www.electropedia.org/
– ISO Online browsing platform: available at http://www.iso.org/obp
3.1 Terms and definitions
3.1.1
ESD risk assessment
assessment of the risk of damage to ESDS resulting from ESD events or exposure to
electrostatic fields
3.1.2
process
unique combination of tools, materials, methods, and people engaged in producing a defined
output
Note 1 to entry: The term "process" can refer to a complete assembly process or a minor step, such as the pick
operation of a pick-and-place process.
3.1.3
process assessment
methodological framework to evaluate the process capabilities regarding defined parameters
3.1.4
process capability
parameters for different ESD risks that allow safe handling of items with a given ESD withstand
voltage or a given ESD withstand current
3.2 Symbols and abbreviated terms
3.2.1 Symbols
C capacitance
C capacitance of a device (component) in the CDM qualification tester
CDM
C capacitance of a conductor in the process
conductor
C source capacitance of an ESD model
ESD
C capacitance of the ESDS in the process
ESDS
C source capacitance of the HBM
HBM
C gate capacitance
g
C source capacitance of the MM
MM
C capacitance of personnel in the process
personnel
I, I(t) (time dependent) current
I current attenuation ratio
atten
I charged device model withstand current (device level qualification)
CDM
I human body model withstand current (device level qualification)
HBM
I machine model withstand current (device level qualification)
MM
I discharge current of personnel
personnel
I peak discharge current of a metal object (reference object)
ref
L inductance
L series inductance
series
Q charge
Q charge required for breakdown
br
Q charge stored on a conductor in the process
conductor
Q initial charge stored in the capacitance of the ESD model
ESD
Q charge stored on the ESDS
ESDS
Q initial charge stored in the capacitance of the HBM
HBM
Q charge stored on personnel in the process
personnel
R resistance
R arc resistance
arc
R contact resistance
contact
R resistance point to ground
g
R human body model network resistance (device level qualification)
HBM
R input impedance of an oscilloscope
input
R point-to-point resistance
p-p
R surface resistance
S
R resistance of a sample under test
sample
R series resistance
series
R shunt resistance (of a measurement target)
shunt
R total resistance
total
R volume resistance
V
t time
t start time (for example, of a discharge waveform)
t pulse length of a machine model pulse (device level qualification)
pm
t end time (for example, of a discharge waveform)
end
V, V(t) (time dependent) voltage
V voltage at time t
0 0
V charged device level withstand voltage (device level qualification)
CDM
V charging (voltage) of a conductor in the process
conductor
V withstand voltage of an ESD model (device level qualification)
ESD
V voltage at the ESDS in the process
ESDS
V gate breakdown voltage
gbr
V human body model withstand voltage (device level qualification)
HBM
V machine model withstand voltage (device level qualification)
MM
V charging (body voltage) of personnel in the process
personnel
W electrical energy
W energy attenuation ratio
atten
W electrical energy stored on a conductor in the process
conductor
W machine model withstand energy (device level qualification)
MM
angular velocity
ω
3.2.2 Abbreviated terms
AHE automated handling equipment
CBE charged board event
CDE cable discharge event
CDM charged device model
CPM charged plate monitor
EGC equipment grounding conductor
EMI electromagnetic interference
EPA electrostatic discharge protected area
ESD electrostatic discharge
ESDS ESD sensitive item or items
ESVM non-contact electrostatic voltmeter
GFCI ground fault circuit interrupter
HBM human body model
IC integrated circuit
MM machine model
PCB printed circuit board
PCBA printed circuit board assembly
RCD residual current device
RH relative humidity
TC test condition (stress level used in CDM qualification tests)
4 Personnel safety
The procedures and equipment described in this document can expose personnel to hazardous
electrical conditions. Users of this document are responsible for selecting equipment that
complies with applicable laws, regulatory codes, and both external and internal policy. Users
are cautioned that this document cannot replace or supersede any requirements for personnel
safety.
Safety requirements for electrical equipment for measurements are given in IEC 61010-1 and
IEC 61010-2-030.
Residual current devices (RCD) or ground fault circuit interrupters (GFCI) and other safety
protection should be considered wherever personnel can come into contact with electrical
sources. Electrical hazard reduction practices should be exercised, and proper grounding
instructions for equipment shall be followed.
Resistance measurements obtained through the use of the test methods described in this
document shall not be used to determine the relative safety of personnel exposed to hazardous
AC or DC voltages.
5 Experience level required
The procedures in this document are for use by personnel possessing advanced knowledge
and experience with electrostatic measurements. The interpretation of the results from the
measurements described in this document requires significant experience and knowledge of
the physics of ESD and the process.
6 Measurement techniques for ESD risk assessment
Specific instruments are needed for specific measurement techniques to perform a proper ESD
risk assessment. The appropriate instruments are required to measure if a material fulfils given
requirements. The resistance of a material is an important parameter for ESD risk assessment.
In many cases, the resistance range of a material that is conductive, dissipative or insulative
range determines the risk scenario. The definition of the resistance ranges for the purpose of
this documents are summarized in Table 1.
Table 1 – Resistance ranges of materials used in this document
Material classification Test method Method description Limits
a R Surface resistance R < 1,0 × 10 Ω
IEC 61340-2-3 S S
Conductor, conductive
material
b,c 4
R Point-to-point resistance
IEC 61340-2-3 R < 1,0 × 10 Ω
p-p
p-p
1,0 × 10 Ω ≤ R < 1,0 ×
S
a R Surface resistance 11
IEC 61340-2-3 S 10 Ω
Dissipative material
b,c 4
R Point-to-point resistance
IEC 61340-2-3 1,0 × 10 Ω ≤ R < 1,0 ×
p-p
p-p
10 Ω
a
R Surface resistance R ≥ 1,0 × 10 Ω
IEC 61340-2-3
S S
Insulator, insulative
material
b,c 11
R Point-to-point resistance
IEC 61340-2-3 R ≥ 1,0 × 10 Ω
p-p
p-p
a
Measurement of R according to IEC 61340-2-3 describes the use of a concentric ring electrode for planar
S
material which is larger than the diameter of the concentric ring electrode.
b
IEC 61340-2-3 describes the point-to-point resistance measurement using either a two-point probe for non-
planar materials and items with small samples or two 2,5-kg electrodes. Either of these test methods may be
used.
c
The results of a measurement of R according to IEC 61340-2-3 can be different compared to the results of a
p-p
measurement of R according to IEC 61340-2-3 due to the usage of different probes.
S
In addition to resistances of materials, the charging status of an object or even the discharge
current waveform of this object can be measured. Each process step can require a different
technique and instrument to measure whether there is a risk to the ESDS being processed.
Clause 6 describes the basic measurement techniques that can be used to assess various risks
in different scenarios.
Table 2 lists instruments that can measure parameters to assess whether there is an ESD risk
for the items handled in a process. Measurement of the actual discharge of the object under
consideration is desirable. The discharge waveform can then be compared with the qualification
waveform, and the risk can easily be assessed. However, measurement of the actual discharge
current waveform is often difficult to achieve, especially in a production environment. Therefore,
indirect parameters can be assessed, such as charging of the object, although this parameter
does not tell the user whether a catastrophic discharge is happening. If it is not possible to
measure charging, measurements such as resistance to ground can be used (see Figure 1). A
detailed description of all the test methods is given in Annex A.
All measurements should be performed with verified instruments to ensure that the
measurements are not influenced by defective instruments.
Due to the sampling nature of the procedures described in this document, deficiencies can exist
that are not detected at the time the measurements are made. The measurement results
obtained are valid only at the time the measurements are made, as validity can change with
time.
Environmental parameters such as temperature, atmospheric pressure and relative humidity
(RH) can significantly impact measurement results.
Table 2 – Overview of possible instruments used for
different scenarios to assess ESD risk
Parameter (Annex A) Personnel Conductors Insulators Devices/PCBs
Current probe
Current probe Current probe
Discharge currents
Pellegrini target –
(Clause A.8)
Pellegrini target CDM test head
CDM test head
Antenna with Antenna with
Current probe
Discharge events
oscilloscope oscilloscope
–
(Clause A.7)
CDM test head
ESD event detector ESD event detector
Charged plate monitor
Walking test kit ESVM ESVM
ESVM
Electrostatic voltage
ESVM Contact voltmeter Contact voltmeter
(Clause A.6) a
Field meter
a a
Contact voltmeter
Field meter Field meter
a
Field meter
Faraday pail Faraday pail
Electrometer
Charge
Electrometer Faraday pail Electrometer
(Clause A.5)
Current probe
Current probe Current probe
Electrostatic fields
Field meter Field meter Field meter Field meter
(Clause A.4)
Resistance
Resistance of material Resistance Resistance Resistance
measurement
contacting ESDS measurement measurement measurement
apparatus
(Clause A.3) apparatus apparatus apparatus
Low resistance meter
Low resistance meter
Resistance
Grounding
Resistance
measurement – –
(Clause A.2)
measurement
apparatus
apparatus
a
Used as non-contact electrostatic voltmeter.

Figure 1 – Direct (best correlation) and indirect (least correlation)
measurements to assess an ESD risk
7 ESD robustness of ESDS used in processes
7.1 General considerations
For a successful ESD risk assessment, one or more of the electrical/physical parameters listed
in Table 2 and the ESD risk assessment flows in Clause 8 should be measured and compared
against set limits. However, the parameters' limits depend on the process, measurement
methodologies and techniques, and ESD robustness of the ESDS. Therefore, it is not possible
to define one limit for the parameters of all ESDS and processes. It is particularly important to
distinguish between handling single devices (components) and electronic assemblies. For
example, a single device with relatively high robustness against a charged device model (CDM)
discharge can be more susceptible to damage once installed on a PCBA. The PCBA has a
larger capacitance than the single device, which can result in more severe stress (higher peak
current, higher charge).
Defining limits requires some knowledge about the ESD robustness of the ESDS that is being
handled in the process and knowledge about the process itself. As the ESD robustness of the
ESDS in this process is better known, and the process is analysed in greater detail, more
accurate limits can be determined. Otherwise, reasonable assumptions should be made.
The discharge event is the most critical point of a process or application and determining the
discharge current is the most direct parameter for ESD risk assessment. Comparing the
discharge current as measured in the process with the withstand current obtained during ESD
qualification tests is theoretically the best approach. However, discharge currents from
qualification data are often unknown and not easily obtainable directly in process
measurements. Hence, more indirect parameters should be used for ESD risk assessment. In
most cases, the charging and the ESD withstand voltage of the ESDS are used for the
assessment. Each uncertainty in the ESD robustness of the ESDS or the knowledge about the
process reduces the accuracy and, consequently, results in a higher effort combined with a
possible larger margin that should be taken to exclude any risk.
Subclause 7.2 discusses how the withstand current of single devices of the different discharge
scenarios can be derived either from qualification data or from limits defined in IEC 61340-5-1.
A similar discussion of withstand currents of electronic assemblies is outlined in 7.3. These
withstand currents are the basis for assessing the limits of the measurement parameters listed
in Table 2 and the ESD risk assessment flows in Clause 8.
Subclause 7.4 discusses damage to voltage sensitive devices by charge injection from an
electrostatic field or discharge source.
7.2 ESD withstand currents of single devices (components)
7.2.1 Human body model
Component manufacturers use the human body model (HBM) test to determine the sensitivity
of the ESDS to discharge from a simulated charged person. The present HBM qualification
procedure and the waveforms are described in IEC 60749-26 [4] or ANSI/ESDA/JEDEC JS-001
[5]. Typically, in HBM qualification, the HBM withstand voltage V is reported, not the HBM
HBM
discharge current I , which is the real damaging parameter. However, the HBM withstand
HBM
current I can be derived from the HBM withstand voltage by I = V /R with R
HBM HBM HBM HBM HBM
= 1 500 Ω being the serial resistance in the HBM discharge network. This relation is a worst-
case assumption as the possible serial resistance in the ESDS is neglected.
– If the HBM robustness in terms of withstand voltage V of the component is known, the
HBM
withstand current can be calculated by I = V /R .
HBM HBM HBM
EXAMPLE 1 A component with an HBM withstand voltage of 1 000 V has an HBM withstand current of I
HBM
= 1 000 V/1 500 Ω = 667 mA.
– If the HBM robustness of the component is unknown, any of the following approaches can
be adopted:
• If similar products with the same power supply concept and set of I/O cells have been
qualified according to HBM, these qualification values can be used as HBM withstand
voltage.
• 100 V HBM withstand voltage can be used as a reasonable lower limit of ESDS that can
be handled in an EPA according to IEC 61340-5-1. For most components, this value can
be quite conservative but still can be achieved rather easily in a process.
EXAMPLE 2 The maximum HBM withstand current for a component with 100 V HBM withstand voltage is
then I = 100 V/1 500 Ω = 67 mA.
HBM
• If the application does not tolerate any ESD related failures, the assumed HBM withstand
voltage can be lowered; however, a lower HBM withstand voltage can require additional
ESD control measures.
EXAMPLE 3 If for a component a HBM withstand voltage of 50 V is assumed, the HBM withstand current
is I = 50 V/1 500 Ω = 33 mA.
HBM
7.2.2 Discharge of charged conductors
The risk of a component being damaged by contact to a charged conductor while at least one
pin of the component is at a different potential (typically grounded) was previously thought to
correlate to the "machine model" (MM) test. However, MM is no longer used for component ESD
qualification due to severe deficiencies in repeatability and reproducibility. Therefore, MM
qualification results are typically not available.
NOTE A discharge of a charged conductor to a floating device is modelled by CDM because it is the closest
approximation.
– If HBM qualification is available, HBM thresholds divided by ten can act as a reasonable
approach to correlate with a charged conductor's discharge into a component at a different
potential. According to [6], the correlation between V and V is in the range of 3:1 to
HBM MM
30:1. According to [7] (withdrawn) and [8], the MM withstand current is 1,75 A per 100 V.
EXAMPLE 1 If the HBM withstand voltage of a component is 500 V, the corresponding MM withstand voltage
can be estimated to be V = V /10 = 50 V, and the MM withstand current to be I = 1,75 A × (V /100 V)
MM HBM MM MM
= 875 mA.
– If the HBM robustness of the component is unknown, any of the following approaches can
be adopted:
• 35 V MM robustness against a discharge of a charged conductor can be used as a
reasonable lower limit of ESDS that can be handled in an EPA according to
IEC 61340-5-1. For most of the components, this value can be quite conservative, but
still can be achieved rather easily in a process.
EXAMPLE 2 The maximum MM withstand current for a component with 35 V MM withstand voltage is then
I = 1,75 A × (35 V/100 V) = 613 mA.
MM
• If the application does not tolerate any ESD-related failures, the assumed MM withstand
voltage can be lowered; however, a lower MM withstand voltage can require additional
ESD control precautions.
EXAMPLE 3 The maximum MM withstand current for a component with 10 V MM withstand voltage is then
I = 1,75 A × (10 V/100 V) = 175 mA.
MM
7.2.3 Charged device model
The phenomenon of a charged component or a component in the presence of an electric field
being discharged when contacted by a conductive item i
...