Basics of Electrostatic Discharge
Part Six---ESD Standardsby
The ESD Association
Special to Compliance Engineering Magazine
September 24, 1998
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 Black has been replaced by green, blue and gold.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 S8.1-ESD Awareness Symbols; ESD ADV2.0-ESD Handbook; EIA 625-Requirements for Handling Electrostatic Discharge Sensitive Devices, MIL-STD-1686-Electrostatic Discharge Control Program; 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.
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.
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 25 documents: 8 full standards, 6 standard test methods, 6 draft standards and 5 advisories. 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.
New ESD Association Standards Classifications and Definitions
After several months of intense work and discussion, the ESD Association Standards Committee has redefined its various standards documents to add clarity and usability to them. Prior to this redefinition, the Association dealt with two types of documents. Association standards often were test methods that may or may not have had any specifications associated with them. Advisories were simply informational in nature. With the new definitions, there are now four types of standards documents with more 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.
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.
Perhaps one of the more intriguing changes in ESD standards has been the organizational cooperation developing between various groups. In revising EIA541, the EIA has implemented a cooperative effort with the ESD Association. EIA will produce the document and develop the specifications within it. The ESD Association will develop the test methodology to be referenced within the document.
Another cooperative effort is underway between the ESD Association and the U.S. Department of Defense. The ESD Association is preparing an update to MIL-STD- 1686 as a commercial standard. Defense agencies will then use that document 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.
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.
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 work stations.
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.
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.
EN100015: Protection of Electrostatic Sensitive Devices
Adopted in 1992 and 1993, this European Norm covers ESD handling practices for electronic devices.
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.
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.
EOS/ESD S4.1-1997: Worksurfaces - Resistance Measurements
This Standard Test Method establishes test methods for measuring the electrical resistance of worksurface materials used at workstations for protection of ESD susceptible items.
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.
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 procedures for testing, evaluating and classifying the ESD sensitivity of components to the defined Human Body Model (HBM).
ANSI ESD S5.2-1994: 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.
ANSI EOS/ESD S6.1-1991: 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.
ANSI ESD S8.1-1993: ESD Awareness Symbols
Three types of ESD awareness symbols are established by this document.
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 discharge shielding bags.
ESD STM12.1-1997: Seating-Resistive Characterization
This draft standard provides test methods for measuring the electrical resistance of seating used in an ESD control program.
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 DS5.2-1996: Electrostatic Discharge Sensitivity Testing-Machine Model.
This draft standard defines a test method that simulates an ESD event occurring from a low resistance source. 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 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 DS54.1-1997: Floor Materials and Footwear-Resistance Measurement in Combination with a person
This Draft Standard provides a test method for measuring the electrical resistance of floor materials, footwear, and personnel together as a system.
ESD DS54.2-1997: Floor Materials and Footwear-Voltage Measurement on a Person.
This Draft Standard provides a test method for measuring the electrostatic voltage on a person in combination with floor materials and footwear as a system.
ESD DS20.20-1998: Electrostatic Discharge Control Program
This Draft Standard covers the requirements necessary to design, establish, implement and maintain an ESD control program for ESD sensitive items that are susceptible to discharges greater than or equal to 100 volts HBM.
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 and reviews procedures and problems associated with various test methods that are often used to evaluate triboelectrification characteristics.
ESD ADV53.1-1995: ESD Protective Workstations
This Advisory defines the minimum requirements for a basic ESD protective workstation used in ESD sensitive areas. It also provides a test method for evaluating and monitoring workstations.
Sources of Standards
ESD Association, 7900 Turin Road, Building 3, Suite 2, Rome, NY 13440. Phone: 315-339-6937. Fax: 315-339-6793.
Electronic Industries Alliance/JEDEC, 2001 Pennsylvania Ave., NW, Washington, DC 20006. Phone: 202-457-4900. Fax: 202-457-4985.
International Electrotechnical Commission, 3, rue de Varembe, Case postale 131, 1211 Geneva 20, Switzerland. Fax: 41-22-919-0300.
Military Standards, Naval Publications and Forms Center, 5801 Tabor Avenue, Philadelphia, PA 19120.
Global Engineering Documents, 15 Inverness Way East, Englewood, 80112. Phone: 800-854-7179. Fax: 303-397-2740
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