Antistatic bag
ESD-protective packaging is used for storing electronic components, which are prone to damage caused by electrostatic discharge. They generally are in the form of a bag, hence the colloquial name ESD bag. They generally have a layer of weakly conductive material on the inside to prevent static charges from building up from rubbing and to make sure any static discharge flows through the bag and not the contents. The former property is called being antistatic; the latter is called being static-dissipative. According to JESD 625-A, a material being conductive does not imply that it will be antistatic; specialized triboelectric tests must be performed to make sure.
Some ESD packaging incorporate a higher-conductivity layer to form a Faraday cage. This not only provides against electrostatic discharge, but also external electric fields. This protection is relevant if a static discharge happens between the outside of the bag and another object, as the ensuing electrostatic field will penetrate a non-conductive bag and generate a voltage on the inside of the bag. ANSI/ESD S541 Appendix E defines a static shielding test, which applies a discharge to the outside of the bag. A voltage sensor is placed inside the bag to understand how well the bag shields.
Standards that describe ESD-protective packaging include JESD 625-A, ANSI/ESD S541, and ANSI/ESD S20.20. ANSI/ESD S541 defines a few ways to test ESD packaging.
Construction
Most ESD packaging are mainly made out of plastic as plastic is cheap, flexible, and harder to tear compared to foil. However, since most plastic is not conductive, special treatment must be done to make them ESD-protective.; Dissipative "pink poly" bag
; Semi-conductive "black poly" bag
; Shield bag
; Moisture-barrier bag
Both pink and black polyethlene also exist in other forms, such as foam, bubble wrap, and rigid pieces such as boxes. The foam is used for storing individual leaded components by piercing the leads into the foam.
Use
Multiple layers of protection are often used to protect from both mechanical damage and electrostatic damage. A protected device can be packaged inside a metalized PET film bag, inside a pink polyethylene bubble-wrap bag, which is finally packed inside a rigid black polyethylene box lined with pink poly foam.It is important that the bags only be opened at static-free workstations.