INTRODUCTION TO ESD

What is Electrostatic Discharge?

ESD is the flow of electricity between two electrically charged objects when they come into close proximity. An everyday example includes the shock we sometimes receive when we touch a metal doorknob. Another example of an ESD event would be a lightning bolt. Before an ESD event occurs, there must first be a build-up of electrostatic discharge which occurs as a result of two substrates rubbing together. When this happens, one substrate becomes positively charged and the other becomes negatively charged, providing the ideal circumstances for an ESD event to occur.

Associated risks of ESD

Electronic components are susceptible to damage from low voltage ESD events. Many electronic components may become damaged by when exposed to ESD as low as 10 volts. Whether you’re handling, storing, transporting, or installing static sensitive components, it is essential that measures are put in place to prevent an ESD event from damaging static sensitive components. ESD damage to components is invisible to the naked eye, so there’s no way of knowing that an ESD event has damaged your device which could cause the entire system that it’s installed in to fail. Precautions should be made to ensure you, your equipment, and your work area are all grounded to prevent ESD damage to sensitive components and devices.

ESD risks may come in two different forms:

• Latent Defect: Component partially damaged but passes inspection. Component will continue to perform as normal but may eventually fail. This can cause more returns, more warranty costs and more irate customers


• Catastrophic Failure: Detectable by inspection and actions may be put in place to ensure the device is scrapped before it gets installed or sold

ESD Standard

EN 61340 Part 5-1: Protection of electronic devices from electrostatic phenomena is a widely recognised standard used by most companies when designing and implementing their ESD control plan. When putting together your ESD control plan, it is important to carry out the below actions:

Identify ESD Area
Identify ESD sensitive items
Provide ESD control training

Preventive actions

• Ground all conductors, including yourself. Ensure wrist straps and foot grounders work by testing them daily


• Ground cord to common point ground to equipment ground


• Ground ESD floor mats via a ground cord to equipment ground


• Neutralise insulators with Ionisers as these cannot be grounded


• Shield ESD sensitive components when kept outside of the ESD Protected Area (EPA). This may be done by using a Static Shielding Bag or a covered conductive tote box


• Swap your regular equipment for ESD equipment including ESD smocks and gloves, Antistatic tape, dissipative floor finishes and other ESD equipment used in your work area

ESD Bag Selector

ESD bags are used to store static sensitive components and devices which are prone to damage. There are many different types of ESD bags on the market and it’s important to be able to differentiate between them and choose the right one for your application. Below are the most commonly used ESD bags available:

• Metalised Static Shielding Bags: Designed for use outside the ESD protected area. These bags provide a “Faraday Cage” and ultimate protection against ESD


• Moisture barrier bag: Designed to package and protect moisture sensitive components, usually surface mount devices. These bags also provide the ultimate ESD protection and restrict the transmission of water vapour to make them the ideal moisture proof packaging solution. These bags may be vacuum sealed to ensure maximum protection from vapour, humidity and ESD


• Black Conductive Bags: For use within the ESD protected area only when the operator is grounded


• Pink Antistatic Bags: Do not provide shielding against ESD however they may be used to store and transport non ESD sensitive products within an ESD protected area. These bags are capable of dissipating static charge to ground preventing static charge build up on the bag or device. The bag will not charge up when rubbed against another substrate