Frequently Asked Questions about ESD-Safe Tapes and Label Materials
What is ESD?
It stands for electrostatic discharge. ESD occurs when a static charge is released, in the form of electrical current, into a static sensitive device. If the charge exceeds the specified thresholds of the device, immediate and/or latent damage can occur.
How does electrostatic charge occur?
Electrostatic charge occurs when two dissimilar surfaces come in contact with one another and are subsequently separated (e.g. removing a liner from a label or tape) or when a charged insulator (e.g. label or tape that has had its liner removed) is brought in close proximity with an electrical device causing charge polarization on the device.
What is the standard for qualifying ESD products and manufacturing?
ANSI/ESD S20.20 standard and its international equivalent IEC 61340 define the ESD control plan. Electronics manufacturers (OEMS, converters, EMS, CM, ODM, etc.), must have an S20.20 qualified control plan in place
to manufacture static sensitive devices.
The standard also includes the ANSI/ESD S541 standard that all process required insulators (e.g. labels and tapes) must meet if they are to be included in an ESD control plan.
Who developed it?
The ESD Association in conjunction with the ANSI standards group.
What does the ANSI/ESD S20.20 control?
The ANSI/ESD S20.20 standard defines the ESD control plan required to help prevent ESD damage to electrostatic devices during manufacturing.
Who needs to comply with the standard?
Any electronics manufacturer (OEM, EMS, ODM, CM, etc.) who makes static sensitive devices (i.e. PCBs, chips, storage devices, etc.) must be certified as being compliant to the ANSI/ESD S20.20 standard.
Is there a section within ANSI/ESD S20.20 that relates directly to labels and tapes?
Yes, the ANSI/ESD S541 standard governs packaging materials that are used within an ANSI/ESD S20.20 controlled safe area and includes provisions for process-related insulators, such as labels and tapes.
Are liners also considered charged insulators and governed by the ANSI/ESD S541 standard?
Yes, liners are considered charged insulators. If you remove the liner from a label or tape within an ANSI/ESD S20.20 ESD controlled safe area it will have electrostatic charges. If these charges are higher than the device thresholds they can cause immediate or latent damage to the devices.
What test within the ANSI/ESD S541 standard are the labels, tapes and liners tested to?
STM S11.11 is the test for surface resistance. Static dissipative materials must have surface resistances >104 and <1011 Ohms.
ESD ADV 11.2 defines the test for the charge accumulated charges on tapes and labels after their liners have been removed. To qualify, these charges must be less than 125volts/in if used within 12".
What are the label, tapes and liners that pass the ANSI/EDS S541 requirement referred to?
The proper term for these materials is low charging. They are also referred to as static dissipative, ESD and/or antistatic.
Does Polyonics labels and tapes pass the ANSI/ESD S541 standards?
Are there other methods available to manufacturers that can help control electrostatic charges rather than using low charging tapes and labels?
Ionizers are very effective and widely used. They add positively and negatively charged atoms and molecules (ions) to the air that is then blown over the static sensitive devices with the ions neutralizing the charges. However, the ionization process takes a finite amount of time to work. So, if a non-ESD label or tape is quickly brought near or applied to a static sensitive device, the ionization may not be able to neutralize the charges quickly enough and damage can occur.
It is highly recommended that ESD-Safe labels and tapes always be used in conjunction with ionization.