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Basics of Electrostatic Discharge
Part Six---ESD Standards*
In a world that is characterized by change, the ESD industry seems
to have jumped into the swirling eddy head-first. 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Black has been replaced by green, blue and gold.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, 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.
That's where standards come into play. They help define the sensitivity of
the products manufactured and used. They help define the performance requirements
for various ESD control 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
of ESD control products; users of ESD control products; 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 auditing 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; ESD ADV2.0-ESD Handbook; EIA
625-Requirements for Handling Electrostatic Discharge Sensitive Devices; or
EN100015-Protection of Electrostatic Sensitive Devices.
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 EIA 541-Packaging of Electronic Products for Shipment.
A third group of documents covers the standardized test methods used to evaluate
products and materials. Historically, the electronics industry has relied
largely on test methods established for other industries or even other materials
(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 developed and issued
specific standards and specifications with regard to ESD control. Once a primary
developer of ESD standards, US military agencies are taking a less proactive
approach, relying on commercially developed standards rather than developing
standards themselves. For example, the ESD Association has received the assignment
from the Department of Defense to convert MIL-STD-1686 into a commercial standard.
Among current military standards, MIL-STD-1686 - Electrostatic Discharge
Control Program and MIL-HDBK-263 - Electrostatic Discharge Control
Handbook are the predominant documents. The 1686 standard requires vendors
to classify the ESD susceptibility of their components and have an ESD control
program in place. The accompanying 263 Handbook provides guidelines and suggestions
for ESD control programs and procedures.
Electronic Industries Alliance/JEDEC
The Electronic Industry Alliance (EIA) and EIA's Joint Electronics Development
Engineering Council (JEDEC) are also active in standards development. EIA
541 -- Packaging Material Standards for ESD Sensitive Items specifies
test methods for the evaluation of packaging materials for protection of ESDS
parts during shipment. JEDEC's EIA 625 Requirements for Handling Electrostatic-Discharge-Sensitive
(ESDS) Devices establishes methods for semiconductor manufacturers, distributors,
processing and testing facilities and users to use in protecting components
that have human body model sensitivities of 200 volts or greater.
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. It also represents the US on the International
Electrotechnical Commission Technical Committee 101-Electrostatics.
The ESD Association has published 27 standards documents and 4 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. In revising EIA541, the EIA and the ESD Association
have implemented a cooperative effort to update the standard.
Another cooperative effort is underway between the ESD Association and the
U.S. Department of Defense. The ESD Association prepared a commercial version
of MIL-STD-1686. It is anticipated that defense agencies will use that
commercial version as a reference.
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.
Principal 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.
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.
EIA/JEDEC
EIA541-Packaging Material Standards for ESD Sensitive
Items
This document covers packaging materials and definitions of material types
for ESD sensitive items.
EIA-625: Requirements for Handling Electrostatic-Discharge-Sensitive (ESDS)
Devices
This voluntary standard establishes minimum requirements for ESD control
methods and materials used to protect electronic devices that have human body
model sensitivities of 200 volts or greater. It is applicable to semiconductor
manufacturers, semiconductor distributors, semiconductor processing and testing
facilities, and semiconductor users. It is currently being revised and updated
with a reduced scope.
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
Standards, Standard Test Methods and Standard
Practices have completed the industry comment and review process,
and the document has been approved by the Standards Committee as a Final Standard
Document.
ESD S1.1-1998: Evaluation, Acceptance, and Functional Testing of Wrist
Straps.
A successor to the 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.
ANSI EOS/ESD S3.1-1991: 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 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. 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 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.
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.
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.
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 Measurement
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.
Draft Documents
Draft documents have not yet completed
an industry comment and review stage necessary before being issued as full
standards documents. Draft documents are subject to revision before being
approved as full standards documents.
ESD DSP3.3-1997: Periodic Verification of Air Ionizers.
This Draft Standard practice provides a measurement technique to periodically
determine ion balance and charge neutralization time for ionizers in actual
use locations.
EOS/ESD DS5.3-1996: Electrostatic Discharge Sensitivity Testing - Charged
Device Model
This Draft Standard establishes a test method for evaluating the ESD sensitivity
of active and passive components to a defined charged device model.
ESD DSP10.1-1999: Automated Handling Equipment
This draft Standard Practice provides test methods for evaluating the
ESD ground integrity; charge generation and charge accumulation on devices
in automated handling equipment
ESD DS11.12-1996: Volume Resistance Measurement of Static Dissipative
Planar Materials
This Draft Standard provides test methods for measuring the volume resistance
of static dissipative, planar materials.
ESD DS13.1-1999: Measuring Electrical Potential from Electrical Soldering
& Desoldering Hand Tools
This Draft Standard provides Test Methods for measuring the electrical
leakage and tip to ground reference point resistance of electric soldering/desoldering
hand tolls. It also provides parameters for EOS safe soldering operations.
Advisory Documents
Advisory Documents 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 ADV2.0-1994: ESD Handbook
The ESD Handbook is a complete guide to static control in the work
place. Nineteen chapters cover ESD basics, control procedures, auditing, symbols,
device testing, standards.
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 unrepeatable if used to give more exact
values 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.
Sources of Standards
- ESD Association, 7900 Turin Road, Building 3, Rome, NY
13440. Phone: 315-339-6937. Fax: +1 315-339-6793. Web Site: http://www.esda.org
- Electronic Industries Alliance/JEDEC, 2001 Pennsylvania Ave., NW, Washington,
DC 20006. Phone: 202-457-4900. Fax: 202-457-4985. Web Site: http://www.eia.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.
ESD Basics:
Part One---An Introduction to ESD
Part Two---Principles of ESD Control
Part Three---An Overview of ESD Control Procedures
and Materials
Part Four---Auditing and Training
Part Five---Device Sensitivity and Testing
Part Six---ESD Standards
November, 1999
*Article prepared by the ESD Association and originally published in Compliance
Engineering magazine
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