The
electronics industry is continually shifting. Device density and technology
is more complex. Electronics manufacturing is more heavily reliant
on out-sourcing. The ESD industry seems to have jumped into this swirling
eddy headfirst. ESD control programs have mushroomed. Black has been
replaced by green, blue and gold. Shielding bags dominate the warehouse.
Ionizers exist along side wrist straps and ground cords. An early
history of "smoke and mirrors," magic and lofty claims of performance
is rapidly and safely being relegated to the past.
Today,
more than ever, meeting the complex challenge of reducing ESD losses
requires more than reliance on faith alone. Users require a way
to legitimately evaluate and compare competing brands and types
of products. They need objective confirmation that their ESD control
program provides effective solutions to their unique ESD problems.
Contract manufacturers and OEM's require mutually agreed-upon ESD
control programs that reduce duplication of process controls.
That's
where standards come into play. They provide guidance in developing
programs that effective address ESD process control. They help define
the sensitivity of the products manufactured and used. They help
define the performance requirements for various ESD control materials,
instruments, and tools. Standards are playing an ever-increasing
role in reducing marketplace confusion in the manufacture, evaluation,
and selection of ESD control products and programs.
The Who and
Why of Standards
Who
uses ESD standards? Manufacturers and users of ESD sensitive devices
and products, manufacturers and distributors of ESD control products,
certification registrars, and third party testers of ESD control
products.
Why
use ESD standards? They help assure consistency of ESD sensitive
products and consistency of ESD control products and services. They
provide a means of objective evaluation and comparison among competitive
ESD control products. They help reduce conflicts between users and
suppliers of ESD control products. They help in developing, implementing,
auditing, and certifying ESD control programs. And, they help reduce
confusion in the marketplace. In the United States, the use of standards
is voluntary, although their use can be written into contracts or
purchasing agreements between buyer and seller. In most of the rest
of the world, the use of standards, where they exist, is compulsory.
Key Standards
and Organizations
Just
20 years ago, there were relatively few reliable ESD standards and
few ESD standards development organizations. Today's ESD standards
landscape is not only witnessing an increase in the number of standards,
but also increasing cooperation among the organizations that develop
them.
Today's
standards fall into three main groups. First, there are those that
provide ESD program guidance or requirements. These include documents
such as ANSI ESD S20.20-1999 Standard for the Development
of an ESD Control Program, ANSI/ESD S8.1-ESD Awareness Symbols,
or ESD TR20.20-ESD Handbook.
A
second group covers requirements for specific products or procedures
such as packaging or grounding. Typical standards in this group
are ANSI/ESD S6.1-Grounding or ESD S11.11 for Shielding
Bags.
A
third group of documents covers the standardized test methods used
to evaluate products and materials. Historically, the electronics
industry relied heavily on test methods established for other industries
or even other materials (e. g., ASTM-257-DC Resistance or Conductance
of Insulating Materials). Today, however, specific test method
standards focus on ESD in the electronics environment, largely as
a result of the ESD Association's activity. These include standards
such as ESD S5.1-Device Testing, Human Body Model and ANSI/ESD
S7.1: Floor Materials Resistive Characterization to cite
just a few.
Who Develops
Standards?
Standards
development and usage is a cooperative effort among all organizations
and individuals affected by standards. There are several key ESD
standards development organizations.
Military
Standards
Traditionally,
the U.S. military spearheaded the development of specific standards
and specifications with regard to ESD control in the U.S. Today,
however, U.S. military agencies are taking a less proactive approach,
relying on commercially developed standards rather than developing
standards themselves. For example, the ESD Association completed
the assignment from the Department of Defense to convert MIL-STD-1686
into a commercial standard.
ESD
Association
The
ESD Association has been a focal point for the development of ESD
standards in recent years. An ANSI-accredited standards development
organization, the Association is charged with the development of
ESD standards and test methods. The Association also represents
the US on the International Electrotechnical Commission Technical
Committee 101-Electrostatics.
The
ESD Association has published 26 standards documents and 9 technical
reports. These voluntary standards cover the areas of material requirements,
electrostatic sensitivity, and test methodology for evaluating ESD
control materials and products. In addition to standards documents,
the Association also publishes a number of informational advisories.
ESD
Association Standards Classifications and Definitions
There
are four types of ESD Association standards documents with specific
clarity of definition. The four document categories are consistent
with other standards development organizations. These four categories
are defined below.
Standard:
A precise statement of a set of requirements to be satisfied by
a material, product, system or process that also specifies the procedures
for determining whether each of the requirements is satisfied.
Standard
Test Method: A definitive procedure for the identification,
measurement and evaluation of one or more qualities, characteristics
or properties of a material, product, system or process that yields
a reproducible test result.
Standard
Practice: A procedure for performing one or more operations
or functions that may or may not yield a test result. Note: If a
test result is obtained, it may not be reproducible between labs.
Technical
Report: A collection of technical data or test results published
as an informational reference on a specific material, product, system,
or process.
As
new documents are approved and issued, they will be designated into
one of these four new categories. Existing documents are being reviewed
and will be reclassified as appropriate.
International
Standards
The
international community, led by the European-based International
Electrotechnical Commission, has also climbed on board the standards
express. Europe's CENELEC has issued a European electrostatic standard
EN100015 - Protection of Electrostatic Sensitive Devices
that was adopted as a European Norm. Additional work by the IEC
to will result in a comprehensive series of standards that may someday
be the successor to EN100015.
Japan also has released its proposed version of a national electrostatic
Standard, which also shares many aspects of the European and U.S.
documents.
Organizational
Cooperation
Perhaps
one of the more intriguing changes in ESD standards has been the
organizational cooperation developing between various groups. One
cooperative effort was between the ESD Association and the U.S.
Department of Defense, which resulted in the Association preparing
ANSI/ESD S20.20 as a successor to MIL-STD-1686.
Internationally,
European standards development organizations and the ESD Association
have developed working relationships that result in an expanded
review of proposed documents, greater input, and closer harmonization
of standards that impact the international electronics community.
For
users of ESD standards, this increased cooperation will have a significant
impact. First, we should see standards that are technically improved
due to broader input. Second, we should see fewer conflicts between
different standards. Finally, we should see less duplication of
effort.
Summary
For
the electronics community, the rapid propagation of ESD standards
and continuing change in the standards environment mean greater
availability of the technical references that will help improve
ESD control programs. There will be recommendations to help set
up effective programs. There will be test methods and specifications
to help users of ESD control materials evaluate and select products
that are applicable to their specific needs. And there will be guidelines
for vendors of ESD products and materials to help them develop products
that meet the real needs of their customers.
Standards
will continue to fuel change in the international ESD community.
Principle ESD
Standards
U.S.
Military/Department of Defense
MIL-STD-1686C:
Electrostatic Discharge Control Program for Protection of Electrical
and Electronic Parts, Assemblies and Equipment (Excluding Electrically
Initiated Explosive Devices)
This military standard establishes requirements for ESD Control
Programs. It applies to U.S. military agencies, contractors, subcontractors,
suppliers and vendors. It requires the establishment, implementation
and documentation of ESD control programs for static sensitive devices,
but does NOT mandate or preclude the use of any specific ESD control
materials, products, or procedures. It is being updated and converted
to a commercial standard by the ESD Association. Although DOD has
accepted the new ANSI/ESD S20.20 document as a successor, it has
not yet taken action to cancel STD-1686
MIL-HBDK-263B:
Electrostatic Discharge Control Handbook for Protection of Electrical
and Electronic Parts, Assemblies and Equipment (Excluding Electrically
Initiated Explosive Devices)
This document provides guidance, but NOT mandatory requirements,
for the establishment and implementation of an electrostatic discharge
control program in accordance with the requirements of MIL-STD-1686.
MIL-PRF
87893-Workstation, Electrostatic Discharge (ESD) Control
This document defines the requirements for ESD protective workstations.
MIL-B-81705-Barrier
Materials, Flexible, Electrostatic Protective, Heat Sealable
This documents defines requirements for ESD protective flexible
packaging materials.
MIL-STD-129-Marking
for Shipment and Storage
Covers procedures for marketing and labeling ESD sensitive items.
International/European
EN100015:
Protection of Electrostatic Sensitive Devices
Adopted in 1992 and 1993, this European Norm covers ESD handling
practices for electronic devices.
ESD
Association
Standards
Documents
ESD
S1.1-1998: Evaluation, Acceptance, and Functional Testing of Wrist
Straps
A successor to EOS/ESD S1.0, this document establishes test methods
for evaluating the electrical and mechanical characteristics of
wrist straps. It includes improved test methods and performance
limits for evaluation, acceptance, and functional testing of wrist
straps.
ESD
STM2.1-1997: Resistance Test Method for Electrostatic Discharge
Protective Garments
This Standard Test Method provides test methods for measuring the
electrical resistance of garments used to control electrostatic
discharge. It covers procedures for measuring sleeve-to-sleeve and
point-to-point resistance.
ESD
STM3.1-2000: Ionization
Test methods and procedures for evaluating and selecting air ionization
equipment and systems are covered in this standard. The document
establishes measurement techniques to determine ion balance and
charge neutralization time for ionizers.
ESD
SP3.3-2000: Periodic Verification of Air Ionizers.
This Standard Practice provides test methods and procedures for
periodic verification of the performance of air ionization equipment
and systems (ionizers).
ESD
S4.1- 1997(Revised): Worksurfaces Resistance Measurements
This Standard establishes test methods for measuring the electrical
resistance of worksurface materials used at workstations for protection
of ESD susceptible items. It includes methods for evaluating and
selecting materials, and testing new worksurface installations and
previously installed worksurfaces.
ESD
STM4.2-1998: Worksurfaces Charge Dissipation Characteristics
This Standard Test Method provides a test method to measure the
electrostatic charge dissipation characteristics of worksurfaces
used for ESD control. The procedure is designed for use in a laboratory
environment for qualification, evaluation or acceptance of worksurfaces.
ESD
STM5.1-1998 Revised: Electrostatic Discharge Sensitivity Testing
Human Body Model
This Standard Test Method updates and revises an existing Standard.
It establishes a procedure for testing, evaluating and classifying
the ESD sensitivity of components to the defined Human Body Model
(HBM).
ESD
STM5.2-1999 (Revised): Electrostatic Discharge Sensitivity Testing
Machine Model
This Standard establishes a test procedure for evaluating the ESD
sensitivity of components to a defined Machine Model (MM). It also
provides a system of classifying the sensitivity of these components.
The component damage caused by the Machine Model is often similar
to that caused by the Human Body Model, but it occurs at a significantly
lower voltage.
ESD
STM5.3-1999: Electrostatic Discharge Sensitivity Testing
Charged Device Model Non-Socketed Mode
This Standard Test Method establishes a test method for evaluating
the ESD sensitivity of active and passive components to a defined
Charged Device Model (CDM).
ESD
S6.1-1999: Grounding Recommended Practice
This Standard recommends the parameters, procedures, and types of
materials needed to establish an ESD grounding system for the protection
of electronic hardware from ESD damage. This system is used for
personnel grounding devices, worksurfaces, chairs, carts, floors,
and other related equipment.
ANSI
ESD S7.1-1994: Floor Materials Resistive Characterization
of Materials
Measurement of the electrical resistance of various floor materials
such as floor coverings, mats, and floor finishes is covered in
this document. It provides test methods for qualifying floor materials
before installation or application and for evaluating and monitoring
materials after installation or application.
ANSI
ESD S8.1-1993: ESD Awareness Symbols
Three types of ESD awareness symbols are established by this document.
The first one is to be used on a device or assembly to indicate
that it is susceptible to electrostatic charge. The second is to
be used on items and materials intended to provide electrostatic
protection. The third symbol indicates the common point ground.
ESD
S9.1-1995: Resistive Characterization of Footwear
This Standard defines a test method for measuring the electrical
resistance of shoes used for ESD control in the electronics environment.
ESD
SP10.1-2000: Automated Handling Equipment
This Standard Practice provides procedures for evaluating the electrostatic
environment associated with automated handling equipment.
ANSI
ESD S11.11-1993: Surface Resistance Measurement of Static Dissipative
Planar Materials
This Standard defines a direct current test method for measuring
electrical resistance. The Standard is designed specifically for
static dissipative planar materials used in packaging of ESD sensitive
devices and components.
ESD
STM11.12-2000: Volume Resistance Measurement of Static Dissipative
Planar Materials
This Standard Test Method provides test methods for measuring the
volume resistance of static dissipative planar materials used in
the packaging of ESD sensitive devices and components.
ANSI
ESD S11.31-1994: Evaluating the Performance of Electrostatic Discharge
Shielding Bags
This Standard provides a method for testing and determining the
shielding capabilities of electrostatic shielding bags.
ESD
STM12.1-1997: Seating-Resistive Characterization
This Standard provides test methods for measuring the electrical
resistance of seating used to control ESD. The test methods can
be used for qualification testing as well as for evaluating and
monitoring seating after installation. It covers all types of seating,
including chairs and stools.
ESD
STM13.1-2000: Electrical Soldering/Desoldering Hand Tools
This Standard Test Method provides electric soldering/desoldering
hand tool test methods for measuring the electrical leakage and
tip to ground reference point resistance and provides parameters
for EOS safe soldering operation.
ANSI
ESD S20.20-1999: Standard for the Development of an ESD Control
Program
This Standard provides administrative, technical requirements and
guidance for establishing, implementing and maintaining an ESD Control
Program.
ESD
STM97.1-1999: Floor Materials and Footwear Resistance in
Combination with a Person.
This Standard Test Method provides for measuring the electrical
resistance of floor materials, footwear and personnel together,
as a system.
ESD
STM97.2-1999 Floor Materials and Footwear Voltage Measurement in
Combination with a Person
This Standard Test Method provides for measuring the electrostatic
voltage on a person in combination with floor materials and footwear,
as a system.
Advisory
Documents
Advisory
Documents and Technical Reports are not Standards, but provide general
information for the industry or additional information to aid in
better understanding of Association Standards.
ESD
ADV1.0-1994: Glossary of Terms
Definitions and explanations of various terms used in Association
Standards and documents are covered in this Advisory. It also includes
other terms commonly used in the ESD industry.
ESD
ADV3.2-1995: Selection and Acceptance of Air Ionizers
This Advisory document provides end users with guidelines for creating
a performance specification for selecting air ionization systems.
It reviews four types of air ionizers and discusses applications,
test method references, and general design, performance and safety
requirements.
ESD
ADV11.2-1995: Triboelectric Charge Accumulation Testing
The complex phenomenon of triboelectric charging is discussed in
this Advisory. It covers the theory and effects of tribocharging.
It reviews procedures and problems associated with various test
methods that are often used to evaluate triboelectrification characteristics.
The test methods reviewed indicate gross levels of charge and polarity,
but are not necessarily repeatable in real world situations.
ESD
ADV53.1-1995: ESD Protective Workstations
This Advisory document defines the minimum requirements for a basic
ESD protective workstation used in ESD sensitive areas. It provides
a test method for evaluating and monitoring workstations. It defines
workstations as having the following components: support structure,
static dissipative worksurface, a means of grounding personnel,
and any attached shelving or drawers.
ESD
TR 20.20: ESD Handbook
New handbook provides detailed guidance for implementing an ESD
control program in accordance with ANSI/ESD S20.20.
Sources
of Standards
ESD
Association, 7900 Turin Road, Building 3, Rome, NY 13440.
Phone: 315-339-6937. Fax: 315-339-6793.
Web Site: http://www.esda.org
HIS
Global Engineering Documents, 15 Inverness Way East,
Englewood, CO 80112. Phone: 800-854-7179. Fax: 303-397-2740.
Web Site: http://global.ihs.com
International
Electrotechnical Commission, 3, rue de Varembe,
Case postale 131, 1211 Geneva 20, Switzerland.
Fax: 41-22-919-0300.
Web Site: http://www.iec.ch/
Military
Standards, Naval Publications and Forms Center,
5801 Tabor Avenue, Philadelphia, PA 19120.
June
2001
Part OneAn Introduction to ESD
Part TwoPrinciples of ESD Control
Part ThreeBasic ESD Control Procedures
and Materials
Part FourTraining and Auditing
Part FiveDevice Sensitivity and
Testing
Part SixESD Standards
©
Copyright, 1999-2003, ESD Association
7900 Turin Road, Building 3
Rome, NY 13440-2069 USA
Ph: +1 315-339-6937 Fax: +1 315-339-6793
E-mail: info@esda.org