ESD protection is required in all Electronic Manufacturing/Repair Centers for protection against Static Electricity.Electrostatic discharge (ESD) is the sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or dielectric breakdown.
We experience occurrences of static electricity everyday. For example, walking along a carpeted floor in a heated room during winter generates sufficient static electricity to give us a rather shocking experience when we touch the door knob. While this sudden discharge of static electricity does not result in any harm to the human body, it can be very damaging to electronic devices which are sensitive to electrostatic discharge (ESD). It is possible for electronic devices to be damaged by ESD that is imperceptible to the human body.
How does damage from ESD happen?
When a statically-charged person or object touches an electrostatic discharge sensitive (ESDS) device, there is a possibility that the electrostatic charge could be drained through sensitive circuitry in the device. If the electrostatic discharge possesses sufficient energy, damage could occur in the device due to localized overheating. Generally, devices with finer geometries are more susceptible to damage from ESD. The modes in which ESD damage occurs are: (a) Discharge to the device (b) Discharge from the device (c) Field-induced discharge.
Protection for Electrostatic Discharge Sensitive (ESDS) devices.
(A) Work area:
1. It is essential to handle ESDS devices at static-safe workstations. This will prevent yield loss (through catastrophic damage) or, worse, potential reliability failures in the field (through latent damage).
2. Where it is impractical or impossible to use antistatic wrist-straps or remove items that are composed of insulative materials at a static-safe workstation, use an air ionizer designed to neutralize electrostatic charges or apply topical antistats to control generation and accumulation of static charges.
3. When an air ionizer is utilized, it is vital that maintenance procedures and schedules are adhered to in order to ensure that ions generated by the ionizer are sufficiently balanced.
4. Avoid bringing sources of static electricity within 1 meter of a static-safe work bench.
5. Where it is necessary to use air-guns, use special models that do not
generate static charges in the air stream.
1. Any accumulated charge on the body of the human operator should be discharged first before opening the protective container with ESDS devices inside. The discharge can be accomplished by putting a hand on a grounded surface or, ideally, by wearing a grounded antistatic wrist-strap.
2. The use of an antistatic smock for each worker is highly recommended.
3. Education and training on ESD preventive measures is invaluable.
4. A regular audit is also helpful in supporting an ESD program.
(C) Packaging and Transportation:
1. ESDS devices should be contained in a static protective bag or container at all times during storage or transportation.