ANSI ESD-S20.20-2021-EN.pdf - 第27页
ANSI/ESD S20. 20- 2021 19 (This annex is no t part of ESD Association Standa rd A NSI/ESD S20.20- 2021 ) ANNEX F (INFORM ATIVE) – REVISION HI STORY FOR ANSI /ESD S20.20 F .1 2014 Version Foreword: Added CDM and MM sensit…
ANSI/ESD S20.20-2021
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(This annex is not part of ESD Association Standard ANSI/ESD S20.20-2021)
ANNEX E (INFORMATIVE) – STATEMENT OF DIRECTION
These sections may be included in future revisions of ANSI/ESD S20.20. The sections are placed
here for information only and do not have to be implemented.
E.1 Component Threshold Plan
It is important to know what the human body model and charged device model classifications are
for any ESDS item that will come into the process. A plan should be established to determine,
before initial use, that ESDS item thresholds are within the scope of this standard.
The recommended test methods for establishing the HBM and CDM levels are ANSI/ESDA/JEDEC
JS-001 and ANSI/ESDA/JEDEC JS-002, respectively. Ideally, HBM and CDM thresholds would be
available and reported in component datasheets. For example, ANSI/ESD SP5.0 contains a
template for reporting ESD data.
NOTE: The following would be acceptable objective evidence by including the following question in
contractual agreements: "Are any components in this contract outside the scope of ANSI/ESD S20.20
(< 100 volts HBM; < 200 volts CDM)?". Alternatively, a similar question could be included in manufacturing
readiness reviews, design reviews, component datasheet reviews, or any other documented process for
obtaining component information
E.2 Process Assessments
The current version of the standard does not require any data to support claims of handling devices
with 100 volts HBM and 200 volts CDM sensitivities. In a future release of this standard, it is the
goal to require data to support the HBM and CDM claims. There currently are no standards or
standard test methods that can provide data to support the claims. A working group within the ESD
Association is working to provide test methods to "measure" the process. When these test methods
become available, there may be a requirement added to future revisions of this standard to provide
data related to the process capability of the installed ESD process.
Measurements may include, but are not limited to:
• The voltage on devices in the process
• The voltage on printed circuit boards while moving through the process
• Discharge current measurements
For more information, please see ANSI/ESD SP17.1, ESD Standard Practice for the Protection of
Electrostatic Discharge Susceptible Items - Process Assessment Techniques.
ANSI/ESD S20.20-2021
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(This annex is not part of ESD Association Standard ANSI/ESD S20.20-2021)
ANNEX F (INFORMATIVE) – REVISION HISTORY FOR ANSI/ESD S20.20
F.1 2014 Version
Foreword: Added CDM and MM sensitivities to the foreword and a section on Facility Certification.
2.0 Scope: Added 200 volts CDM and 35 volts on isolated charged conductors that this standard
applies.
6.1 ESD Control Program Requirements: Second sentence was revised to "The Program shall
document the lowest level(s) of device ESD sensitivity that can be handled" from "The most
sensitive level of the items to be handled, per the Program, shall be documented."
7.1 ESD Control Program Plan: Product Qualification was added as a required element.
7.3 Product Qualification: Section was added.
7.4 Compliance Verification Plan: Renumbered from 7.3, the content remained the same.
8.2 Personnel Grounding: Note was removed, and the text was made a requirement for garments.
Standing requirements were changed; Method 1 and Method 2 have been changed to one method
of qualification for standing.
8.3 ESD Protected Areas (EPAs): Additional requirement for process essential insulators was
added. Within 1 inch of the ESDS items, the limit for fields was reduced to 125 volts/inch.
Table 3: Wrist Strap Cord Bending Life was removed. Ionization offset voltages were updated for
room systems. Soldering iron requirements were added.
8.4 Packaging: The section was reworded, but the requirements remained the same.
Annex A: Soldering Irons were moved into Table 3. Conveyor systems were added to this section.
Annex B: Updated HBM standard to ANSI/ESDA/JEDEC JS-001 in Table 4.
F.2 Revisions to 2014 Version
F.2.1 December 15, 2021 Version
General changes to improve clarity.
3.0 References: Added reference to MIL-STD-2073-1
4.0 Definitions: Definitions for ESD control items, insulator, conductor, isolated conductor, and
unprotected ESDS item were added and only apply to this document.
6.3 Tailoring: Updated wording for tailoring for clarity. A reference to a new annex with examples
was added.
7.3 Product Qualification: Several changes were made to the requirements. Qualification for ESD
control items that stay on-site can be done at the lowest RH on the site. This does not apply across
multiple sites or materials that leave the site. Qualification records are now required to include
supporting technical reports. Added explanation that the flooring/footwear system cannot use
compliance verification data for qualification. Body voltage measurements must also be made.
7.4 Compliance Verification Plan: Note added that calibration does not imply the equipment can
make measurements.
8.1 Grounding/Equipotential Bonding Systems: A statement that compliance verification of the
grounding system is not required was added. No change in the requirements.
8.3.1 Insulators: The section was updated with a field measurement of where the ESDS item is
handled. The original measurement was retained, and either could be used.
8.3.2 Isolated Conductors: The inclusion of non-contact electrostatic voltmeters and electrostatic
field meters were included with a note on measurement issues.
Table 3: Deleted ANSI/ESD STM4.2 as a qualification for worksurfaces. Added point-to-point
requirements to groundable static control garments and groundable static control garment systems.
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8.4 Packaging: Added Table 4 for packaging requirements, which summarizes ANSI/ESD S541
requirements.
8.4.1 United States Department of Defense (DoD) Packaging Requirements: New section was
added per a request from the DoD to support the withdrawal of Mil-STD 1686.
Annex C Tailoring: New annex was added with examples of tailoring.
Annex E Statement of Direction: New annex that discusses possible additions to ANSI/ESD
S20.20. These are statements at this time and may or may not become requirements in the future.
F.2.2 January 6, 2022 Version (Editorial Changes)
8.2 Personnel Grounding: Changes to the last paragraph. Requirements for a static control
garment system were clarified but not changed.
Table 2: Moved the groundable static control garment system requirement from Table 3 to Table 2
and the product qualification required limit was changed to the system resistance value.
Table 2: Updated the required limits value to include “System Resistance” to ensure that the
measurement is made with a person.