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ANSI/ESD S20.20- 2021 Electrostatic Dischar ge Association (ESDA) standar ds and publications are designed t o serve the public interest by eli minating misu nderstandings betwe en manufactur ers and purchasers, facili t…

ANSI/ESD S20.20-2021

ESD Association Standard

for the Development of an Electrostatic Discharge

Control Program for

Protection of Electrical and Electronic

Parts, Assemblies and Equipment

(Excluding Electrically Initiated Explosive

Devices)

Published January 6, 2022.

Replaces version previously published on December 15, 2021.

Approved October 28, 2021

EOS/ESD Association, Inc.

ANSI/ESD S20.20-2021

Electrostatic Discharge Association (ESDA) standards and publications are designed to serve the

public interest by eliminating misunderstandings between manufacturers and purchasers, facilitating

the interchangeability and improvement of products, and assisting the purchaser in selecting and

obtaining the proper product for his particular needs. The existence of such standards and publications

shall not in any respect preclude any member or non-member of the Association from manufacturing

or selling products not conforming to such standards and publications. Nor shall the fact that a standard

or publication that is published by the Association preclude its voluntary use by non-members of the

Association whether the document is to be used either domestically or internationally. Recommended

standards and publications are adopted by the ESDA in accordance with the ANSI Patent policy.

Interpretation of ESDA Standards: The interpretation of standards in-so-far as it may relate to a specific

product or manufacturer is a proper matter for the individual company concerned and cannot be

undertaken by any person acting for the ESDA. The ESDA Standards Chairman may make comments

limited to an explanation or clarification of the technical language or provisions in a standard, but not

related to its application to specific products and manufacturers. No other person is authorized to

comment on behalf of the ESDA on any ESDA Standard.

THE CONTENTS OF ESDA'S STANDARDS AND PUBLICATIONS ARE PROVIDED "AS-

IS," AND ESDA MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR

IMPLIED, OF ANY KIND WITH RESPECT TO SUCH CONTENTS. ESDA DISCLAIMS

ALL REPRESENTATIONS AND WARRANTIES, INCLUDING WITHOUT LIMITATION,

WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR

USE, TITLE, AND NON-INFRINGEMENT.

ESDA STANDARDS AND PUBLICATIONS ARE CONSIDERED TECHNICALLY SOUND

AT THE TIME THEY ARE APPROVED FOR PUBLICATION. THEY ARE NOT A

SUBSTITUTE FOR A PRODUCT SELLER'S OR USER'S OWN JUDGEMENT WITH

RESPECT TO ANY PARTICULAR PRODUCT DISCUSSED, AND ESDA DOES NOT

UNDERTAKE TO GUARANTEE THE PERFORMANCE OF ANY INDIVIDUAL

MANUFACTURER'S PRODUCTS BY VIRTUE OF SUCH STANDARDS OR

PUBLICATIONS. THUS, ESDA EXPRESSLY DISCLAIMS ANY RESPONSIBILITY FOR

DAMAGES ARISING FROM THE USE, APPLICATION, OR RELIANCE BY OTHERS ON

THE INFORMATION CONTAINED IN THESE STANDARDS OR PUBLICATIONS.

NEITHER ESDA, NOR ITS PRESENT OR FORMER MEMBERS, OFFICERS,

EMPLOYEES OR OTHER REPRESENTATIVES WILL BE LIABLE FOR DAMAGES

ARISING OUT OF, OR IN CONNECTION WITH, THE USE OR MISUSE OF ESDA

STANDARDS OR PUBLICATIONS, EVEN IF ADVISED OF THE POSSIBILITY

THEREOF. THIS IS A COMPREHENSIVE LIMITATION OF LIABILITY THAT APPLIES

TO ALL DAMAGES OF ANY KIND, INCLUDING WITHOUT LIMITATION, LOSS OF

DATA, INCOME OR PROFIT, LOSS OF OR DAMAGE TO PROPERTY AND CLAIMS OF

THIRD PARTIES.

Published by:

Electrostatic Discharge Association

218 West Court Street

Rome, NY 13440

No part of this publication may be reproduced in any form, in

an electronic retrieval system or otherwise, without the prior

written permission of the publisher.

Printed in the United States of America

ISBN: 1-58537-332-X

DISCLAIMER OF

WARRANTIES

DISCLAIMER OF

GUARANTY

LIMITATION ON

ESDA’s LIABILITY

CAUTION

NOTICE

ANSI/ESD S20.20-2021

(This foreword is not part of ESD Association Standard ANSI/ESD S20.20-2021)

FOREWORD

This standard covers the requirements necessary to establish, implement, and maintain an

electrostatic discharge (ESD) control program for activities that manufacture, process, assemble,

install, transport, package, label, service, test, inspect, or otherwise handle electrical or electronic

parts, assemblies, and equipment susceptible to damage by electrostatic discharges greater than

or equal to 100 volts human body model (HBM) and 200 volts charged device model (CDM). The

CDM voltage level used in this document is based on managing process essential insulators to

mitigate field-induced voltages on devices that could lead to damage.

This standard also defines the requirements for isolated conductors. The reference to machine

model (MM) is retained in this standard for the historical association to the MM robustness of

devices to isolated conductors.

HBM and CDM fully characterize the ESD robustness of devices. Therefore, MM testing is no longer

required to qualify devices, and test data may not be available.

This document covers the ESD control program requirements for establishing a program to handle

ESD sensitive (ESDS) items based on the historical experience of both military and commercial

organizations. References include EOS/ESD Association, U.S. Military, and ANSI approved

standards for material properties and test methods. The fundamental ESD control principles that

form the basis of this document are:

A. All conductors in the environment, including personnel, shall be bonded or electrically

connected and attached to a known ground or contrived ground (as on shipboard or aircraft).

This attachment creates an equipotential balance between all items and personnel.

Electrostatic protection can be maintained at a potential above a "zero" voltage ground potential

if all items in the system are at the same potential.

B. Process essential insulators in the environment cannot lose their electrostatic charge by

attachment to ground. Ionization systems provide neutralization of charge on these process

essential insulators (circuit board materials and some device packages are examples of

necessary insulators). Assessment of the ESD hazard created by electrostatic charge on the

process essential insulators in the workplace is required to ensure that appropriate actions are

implemented, commensurate with the risk to ESDS items.

C. Transportation of ESDS items necessitates enclosures in protective materials, although the

type of material depends on the situation and destination. While these materials are not

discussed in the document, it is important to recognize the differences in applications. For more

clarification, see ANSI/ESD S541.

Any relative motion and physical separation of materials or flow of solids, liquids, or particle-laden

gases can generate an electrostatic charge. Common sources of electrostatic charge include

personnel, items made from common polymeric materials, and processing equipment. ESD

damage can occur in several ways, including:

i. A charged object (including a person) coming into contact with an ESDS item.

ii. A charged ESDS item making contact with ground or another conductive object at a different

potential.

iii. An ESDS item making contact with ground or another conductive object while exposed to an

electrostatic field.

Examples of ESDS items include, but are not limited to, microcircuits, discrete semiconductors,

thick and thin film resistors, hybrid devices, printed circuit boards, and piezoelectric crystals. It is

possible to determine device and item susceptibility by exposing the item to simulated ESD events.

The level of sensitivity, determined by testing using simulated ESD events, may not necessarily

relate to the level of sensitivity in a real-life situation. However, the sensitivity levels are used to

establish a baseline of susceptibility data to compare devices with equivalent part numbers from

different manufacturers. Two different models are used for the characterization of electronic items:

HBM and CDM.