Online ESD Program

On-Line ESD Static Audit

Why is Static Control Necessary?

Many electronic components and assemblies used in high technology products can be damaged or degraded by the sudden exchange of static electrical charges. This release of stored energy is called an Electro Static Discharge event or is most commonly referred to as ESD. Independent studies have found that ESD costs manufacturers 4 to 8 percent of total corporate revenues or in excess of $84 billion each year in electronics components, boards and devices being scrapped. Susceptibility of devices to ESD is increasing with the drive to miniaturize electronic devices and increase operating speeds. With smaller and faster devices becoming more sensitive (referred to as Electro Static Discharge Sensitive—ESDS) the costs of damage will continue to rise. These devices are static sensitive to low voltages. The voltage needed to degrade and/or damage these components is so low, only 50 volts, that an employee could not see, hear, or feel it. A person cannot sense below 3,000 volts. Electronic industry estimates are that 25% of all component failures are ESD caused; customer dead-on arrivals are 50% ESD caused; and early life operating failures are more than 50% ESD caused.

What Causes Static Discharge?

Electrostatic charge is most commonly created by the contact and separation of two materials, "triboelectric charging." This creates an imbalance of electrons on a material’s surface. Common sources of ESD include personnel, items made from common polymeric materials, and processing equipment. ESD can damage parts by direct contact with a charged source or by electric fields emanating from charged objects that induce a charge on grounded sensitive items.

ESD damage is classified as either a catastrophic failure or latent defect.

Catastrophic Failure—When an electronic device is exposed to an ESD event, it may no longer function. The ESD event may cause a metal melt, junction breakdown or oxide failure. The device’s circuitry is permanently damaged causing the device failure. Such failures usually can be detected when the device is tested before shipment. If the ESD event occurs after test, the damage will go undetected until the device fails in operation.

Latent Defect—a latent defect is more difficult to identify. A device that is exposed to an ESD event may be partially degraded, yet continue to perform its intended function. However the operating life of the device may be reduced dramatically. A product or system incorporating devices with latent defects may experience premature failure after the user places them in service. Such failures are usually costly to repair and in some applications may create personnel hazards.

Fundamental ESD Control Principles

• All conductors, including personnel, must be electrically connected and attached to a known ground.
• All insulators must be removed to at least 3 feet away from ESDS items.
• Ionization systems provide neutralization of charges on necessary non-conductive items
• Transportation of ESDS items outside an ESD Protected Area requires enclosure in static protective materials. Inside a Protected Area, static dissipative materials may provide adequate protection. Outside a Protected Area, static discharge shielding materials are recommended.

Four basic static control rules have developed worldwide to help control electrostatic discharge damage to sensitive IC’s, PC boards, and electronic systems.

Rule 1: Handle all static sensitive components at a static safeguarded work area. A static safe area is any area that is capable of controlling static charge on conductive materials, people, and non-conductive materials.

Rule 2: Transport all static sensitive components in static shielding containers or packages. A static shield must be capable of protecting from static discharges, as well as static fields.

Rule 3: Make certain that suppliers understand and practice the four basic rules.

Rule 4: Monitor and test all static protection products and materials to make certain they are working.

Purpose of An ESD Audit

An ESD audit will accomplish the following:

1. Turn ESD control into a competitive advantage.
2. Assess the current level of the ESD control program.
3. Identify appropriate ESD protective products or improved methods to satisfy acceptable industry practices.
4. Make suggestions on how to improve the current ESD control program

The purpose of an ESD audit is not to criticize, but rather to offer constructive suggestions that will enable a user to handle sensitive electronic components without destroying them by static discharge. By implementing safe control and handling procedure, the user will become more productive and profitable.

TESSCO primarily uses ANSI/ESD S20.20 as the basis for performing ESD Surveys. This standard, "ESD Association Standard for the Development of an Electrostatic Discharge Control Program for- Protection of Electrical and Electronic Parts, Assemblies and Equipment (Excluding Electrically Initiated Explosive Devices)." The purpose of this document is to provide administrative and technical requirements, as well as guidance, for establishing, implementing and maintaining an ESD Control Program.

TESSCO offers you the opportunity to take a complete on-line ESD Audit (approximately 15 to 20 minutes to complete) or an  Quick ESD checklist  (approximately 5 to 10 minutes). Just complete the form and submit it. We will provide you with specific feedback and recommendations based on your responses.

For more information contact TESSCO
at 800-472-7373 or by email.