Key elements in an ESD Program

Principles of electrostatic safe handling

There are two simple principles we can use to protect ESD sensitive components from ESD damage:

• Only handle sensitive components in an ESD Protected Area (EPA) under protected and controlled conditions
• Protect sensitive devices outside the EPA using ESD protective packaging

What is an EPA?

An EPA is an area that is maintained safe for handling static sensitive components by keeping electrostatic fields and voltages to an insignificantly low level. An EPA should have well defined boundaries so that it is clear where the safe area is entered and left.

Insulating materials are strong ESD sources and so they are excluded from the EPA where possible. Where this is not possible special measures such as ionisers are used to neutralise electrostatic charges.

All non-insulating and conductive objects are grounded, so that electrostatic charge cannot build up on these. Most importantly, all personnel (people are conductive objects!) are grounded so that they do not charge to high voltages. There are two ways in which people are grounded:

• Using a grounded wrist strap (this is the preferred method)
• Using conductive footwear (conductive or dissipative shoes, or heel & toe straps on both feet) in conjunction with a grounded conductive floor.

Three key elements of an effective ESD program

An effective ESD program requires three main parts:

• The ESD Program. This is a document that specifies the equipment used, and procedures followed in order to ensure electrostatic safe handling.
• The Training program. This is required in order to make sure that everyone is aware of, and understands the ESD Program, use of equipment and correct procedures.
• The Audit program. This is required in order to make sure that equipment remains functional, and that the ESD Program procedures are correctly followed.

If any of these is absent, it is likely that the ESD prevention measures will eventually fail. A fourth factor is also extremely important - Management commitment. If Management does not provide the resources and authoritative support required, it is unlikely that the ESD Program will succeed.