A company with an ANSI/ESD S20.20 ESD control program needs to document the program and define ESD protective packaging for ESD sensitive (ESDS) items. Packaging is to be defined for all material movement within the EPA and for outside the EPA. Best practice is to define the required packaging or material handling item on a product’s bill of materials. The ESD packaging is as important as a component part.
Customer contract packaging can take precedence, but otherwise “the organization shall define ESD protective packaging requirements, both inside and outside the EPA per ANSI/ESD S541.” [ANSI/ESD S20.20 section 8.4]
The ESD Association sells most of their documents. However, both ANSI/ESD S20.20 and ANSI/ESD S541 are available as complimentary downloads from www.ESDA.org.
The fundamentals of ESD control include grounding all conductors in the EPA. ESD packaging will have special material composition to lower the resistance so that when grounded, electrostatic charges will be removed to ground.
This is the Summary of ESD Protective Properties ANSI/ESD S541 Table 2:
|Low charging (antistatic)||Materials that have reduced amounts of charge accumulation as compared with standard packaging materials.|
|Dissipative or Conductive Resistance||Provides an electrical path for charge to dissipate from the package.|
|Discharge Shielding||Protects packaged items from the effects of static discharge that are external to the package.|
ANSI/ESD Table 3 lists Test Methods for Electrostatic Protective Packaging:
|Material Property||Test Method||Method Description||Limits|
|Low Charging (Antistatic)||ESD ADV11.2||Tribocharging of tubes, planar materials, bags, unit packs (vibration)||User defined|
|Conductive||ANSI/ESD STM11.11||Surface resistance of planar materials||< 104 ohms|
|ANSI/ESD STM11.12||Volume resistance of planar materials||< 104 ohms|
|Dissipative||ANSI/ESD STM11.11||Surface resistance of planar materials||> 104 to < 1011 ohms|
|ANSI/ESD STM11.12||Volume resistance of planar materials||> 104 to < 1011 ohms|
|ANSI/ESD STM11.13||Surface resistance 2-point electrode||> 104 to < 1011 ohms|
|Shielding||ANSI/ESD STM11.31||ESD Shielding of Bags||< 50 nanojoules|
Note that the unit of measurement for conductive and for dissipative is surface or volume resistance in ohms; not resistivity.
Statshield® bag film construction includes a metalized shielding layer. Shielding bags are designed to dissipate electrostatic charges over their surface, protecting ESDS contents from electrostatic fields and from ElectroStatic Discharge (ESD). Their surface resistance is dissipative, which is recommended when packaging in contact with the ESDS; per ANSI/ESD S541 section A.3 “Dissipative Material for Intimate Contact, to avoid rapid discharge to sensitive items, dissipative materials should be used as the layer of packaging that contacts the item.”
This is also true for enclosed Protektive Pak impregnated dissipative corrugated containers, either closed or with lid in place. The impregnated corrugated has a buried shielding layer that provides the shielding ESD control property so that ESD sensitive items can be stored or transported outside an ESD protected area.
Protektive Pak offers a number of ESD control packaging solutions, including Protektive Pak® Impregnated Dissipative Corrugated Products, Statshield Shielding Bags, Moisture Barrier Bags, Pink Poly Bags, and Labels for use within an ESD protected area (EPA) and for shipping outside an EPA. Protektive Pak products are designed to meet ANSI/ESD S20.20 and the ESD Association Packaging standard ANSI/ESD S541; they provide a great value balancing cost and durability.
ANSI/ESD S541 for the Protection of Electrostatic Discharge Susceptible Items Packaging Materials for ESD Sensitive Items
1. Define what you are trying to protect.
What is the Human-Body Model (HBM) withstand voltage of the most sensitive item? A prerequisite of ESD control is the accurate and consistent identification of ESD susceptible items. Some companies assume that all electronic components are ESD susceptible. However, others write their ESD control plan based on the device and item susceptibility or withstand voltage of the most sensitive components used in the facility. A general rule is treat any device or component that is received in ESD packaging as an ESD susceptible item.
2. Become familiar with the industry standards for ESD control.
A complimentary .pdf of ANSI/ESD S20.20-2014 can be downloaded from the ESD Association web site at www.ESDA.org. Also consider purchasing the ESDA’s ESD Handbook ESD TR20.20-2008.
3. Select a grounding / equipotential bonding system.
The 3rd-wire AC electrical equipment ground is the preferred, recommended ground reference.
4. Determine the method of ground for operators (Personnel Grounding).
The two options for grounding an operator are a wrist strap or foot grounders. Wrist straps must be worn if the operator is seated. If foot grounders are used, an ESD flooring system must be used. In some cases both wrist strap and foot grounders will be used. The 3rd-wire AC electrical equipment ground is the preferred, recommended ground reference.
5. Establish & Identify EPA(s) – ESD Protected Area(s).
ESD Control Plans must evolve to keep pace with costs, device sensitivities, and the way devices are manufactured. Define the departments and areas to be considered part of the ESD Protected Area. Consider if customers and/or subcontractors should be included. Implement access control devices, signs, and aisle marking tape to identify and control access to the ESD Protected Area(s).
6. Select ESD control items to be used in the EPA based on your manufacturing process.
7. Develop Packaging (Materials Handling & Storage) Plan.
When moving ESD susceptible devices outside an ESD protected area, it is necessary for the product to be packaged in an enclosed ESD Shielding Packaging.
8. Use proper markings for ESD susceptible items, system or packaging.
From ANSI/ESD S20.20-2014 section 8.5: “the Organization, in developing the ESD Control Program Plan, shall consider the need for marking.”
9. Implement a Compliance Verification Plan.
From ANSI/ESD S20.20-2014 section 7.4: “A Compliance Verification Plan shall be established to ensure the Organization’s fulfillment of the technical requ.rements of the ESD Control Program Plan”.
10. Develop Training Plan.
From ANSI/ESD S20.20-2014 section 7.2: “Initial and recurrent ESD awareness and prevention training shall be provided to all personnel who handle or otherwise come into contact with any ESDS items.”
11. Make the ESD Control Plan part of your internal quality system requirements.
A written ESD Control Plan provides the “rules and regulations”, the technical requirements for your ESD Control Program. This should be a controlled document, approved by upper management initially and over time when revisions are made. The written plan should include following:
- Qualified Products List (QPL) – A list of EPA ESD control items is used in the ESD control Plan
- Compliance Verification Plan- Includes periodic checking of EPA ESD control items, and calibration of test equipment per manufacturer and industry recommendations.
- Training Plan- An ESD Program is only as good as the use of the products by personnel. When personnel understand the concepts of ESD, the importance to the company of the ESD control program, and the proper use of ESD products, they will implement a better ESD control program improving quality, productivity, and reliability.
ESD Control Program Periodic Verification
Fred Tenzer and Gene Felder, Desco Industries, Inc.
Want to accomplish something important? A familiar formula is write a plan, select the speciﬁcations, and then periodically test to verify that the plan is being implemented according to the test results. This is basically the requirements of an ESD control program, per the ESD Association standard, ANSI/ESD S20.20. This important standard, entitled Development of an Electrostatic Discharge Control Program, covers the requirements necessary to design, establish, implement, and maintain an ESD control program to protect electrical or electronic parts, assemblies and equipment susceptible to ESD damage.
S20.20 is a process document, and provides ESD control plan guidance; one of its requirements is having a “compliance veriﬁcation plan” as a component of the ESD control plan. Per S20.20, paragraph 6.1.3., Compliance Veriﬁcation Plan:
To view more information on ESD Control Program Periodic Veriﬁcation CLICK HERE
Application Photo of Surface Resistance Test Kit
A significant increase in the discipline of implementing the fundamentals of ESD control noted in ANSI/ESD S20.20 Foreword, calls for:
- Ground all conductors in the EPA including people
- Remove all insulators from the EPA or use ionizers for process necessary insulators
- Package ESD sensitive items going outside the EPA in packaging that provides electrostatic discharge shielding
We encourage developing a hatred for insulators. The alternatives are:
Remove the insulative item from the EPA
- Substitute the item with an ESD protective version (such as tape, document holders, material handling containers, plastic bottles, etc.)
- Periodically treat insulative surface with a topical antistat
- Neutralize electrostatic charges using ionization
Other ESD Control Items
Other EPA ESD control items to add to the ESD control program might include shelving, mobile equipment (carts), gloves, and/or seating.
Improve Compliance Verification Plan
- Consider greater frequency of internal audits per ESD TR53
- Use of computer data collection system for wrist straps and footwear testing, continuous monitors, and ionizers
- Use of ground continuous monitors for worksurfaces and other ESD elements
- Test ionizers more frequently, consider self monitoring ionizers, consider computer based data collection
- Increased testing using static field meter to verify that automated processes (like auto insertion, tape and reel, etc) are not generating charges above acceptable limits.
Application Photo of Volt Meter and Software in Factory STM97.2 Testing Voltage Charge on Person (Photograph courtesy of TREK, INC.)
- ESD awareness training for all in the EPA or who may come into the EPA including suppliers
- Testing to verify comprehension and training adequacy
- Training on the proper use of test equipment
- Training on proper compliance verification test procedures
Application Photo CD-ROM ESD Training
Just to maintain a company’s current level of quality and reliability may require a substantial improvement in a company’s ESD control program. Now is the time for improvement as ESD sensitivity withstand voltages continue to get lower and companies may soon be handling class 0A HBM items. To combat HBM failures improved personnel grounding is required. For example, heel grounders should be replaced with full coverage foot grounders. However, most failures are CDM. To combat CDM failures, ionization should be added or improved, and conductive surfaces should be covered with dissipative material. In general, disciple should be enhanced implementing ESD control fundamentals, compliance verification testing should be increased, and training should be improved.
From published article “Now is the Time for ESD Control Programs to be Improved” by Fred Tenzer and Gene Felder. See full article at InCompliance Magazine- September 2012
- Efficient means of shipping or storing ESD sensitive circuit boards and other items in accordance with ANSI/ESD S20.20 & ANSI/ESD S541
- Conductive black foam is non-contaminating, non-corrosive, and non-sloughing
- Conductive black foam used for shipping or storing small components when the components can not come in contact with pink foam
- Conductive crosslink black polyethylene cushion grade foam (3/8″ thick, Rv < 10^4 ohms) laminated to top, and conductive crosslink black polyethylene pin insertion grade foam
- Impregnated corrugated static dissipative surface of 1x 10E6 to < 1x 10E9 ohms per ANSI/ESD S11.1 and IEC 61340-2-3
- Black foam is best for long term use
- No assembly required
- Made in United States of America
|39508||2-1/2" x 1-1/4" x 1"||$1.70||$1.60||$1.42||$1.35|
|39536||3-7/16" x 2-1/8" x 1"||$3.03||$2.85||$2.51||$2.38|
|39542||3-3/4" x 3-3/4" x 1"||$2.66||$2.53||$2.28||$2.16|
|39550||7" x 3-1/2" x 1"||$4.95||$4.65||$4.09||$3.89|
on new product announcements and may change without notice.
ESD control periodic checks
results. This is basically the requirements of an ESD control program, per the ESD Association standard, ANSI/ESD S20.20. This important standard, entitled Development of an Electrostatic Discharge Control Program, covers the requirements necessary to design, establish, implement, and maintain an ESD control program to protect electrical or electronic parts, assemblies and equipment susceptible to ESD damage.
- Provides physical protection with conductive material providing reliable path-to-ground
- Includes wire frame for extra strength
- Product ships flat – easy assembly
- Rtt: 10E2 – 10E4 ohms
- Made in the United States of America
- Conductive Plastic Handles available
- Static Dissipative Foam for bottom, providing ESD and shock protection
- Document Holders
- Made in the United States of America
Click here to view New39300
|39300||17” x 13” x 8-3/4″||
|39301||17” x 13” x 10-3/4″||
|39302||18-5/8” x 15” x 5-7/8″||
|39303||18-5/8” x 15” x 8”||
|39304||18-5/8” x 15” x 12”||
|39305||22-7/8” x 12-7/8” x 6″||
|39306||22-7/8” x 12-7/8” x 18-1/4″||
|39170||ESD Area Sign||
|38911||Plastek™ Open Bin Boxes, 12” x 12” x 4”||$11.70||
|38912||Plastek™ Open Bin Boxes, 18” x 12” x 4”||$13.55||