ESD News

All ESD damage is not created equal. In fact, there are three different types of ESD damage and they can be classified as a catastrophic failure, a latent defect or an upset failure.

As you would imagine, catastrophic failure is the easiest of the three to detect. This type of ESD damage causes some sort of permanent damage such as an oxide failure or a metal melt. The damage done is irreversible. Any device with catastrophic damage is usually found during the testing process and can be dealt with before shipping out.

Latent defects are a little more difficult to spot. This type of damage would allow a device to work properly for the most part, but over time the small amount of damage might affect the life of the device or its ability to function. The issue with latent defects is that the item usually passes testing and is sent to the customer where it may fail.

Lastly, an upset failure is when ESD damages a device or component but not enough to cause complete failure. But while in use, the component may intermittently result in gate failure and cause problems with software and data storage. Just like latent defects, upset failures will pass testing but may have issues in the future.

Damage from electrostatic discharge can happen to components and devices at any stage during its life, including the manufacturing process when the component is being handled or moved, after final inspection and even when it’s in the customer’s possession. It’s important to remember that even though it can’t be seen or felt, ESD damage to electronics can be costly when it comes to both money and reputation.

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If you are reading this, you probably have an idea of what ESD is. But do you know the common sources for ESD? There are three: human body ESD, machine ESD and charge device ESD.

I would imagine that human body ESD is thought of the most when the term ESD is mentioned, and rightfully so because humans probably cause the most ESD damage. Human body ESD is when a human transfers the electrostatic discharge to a part that is static sensitive. Some of the most damaging human errors include ungrounded employees walking around with static sensitive items such as PCBs, employees not wearing appropriate gloves or finger cots and employees walking around with ESD sensitive parts in open bags, bins, totes, etc… Human body ESD can be avoided with the use of a heel/sole ground or wrist strap; both are relatively inexpensive.

Machine ESD is the second cause of ESD damage. This source of damage is caused when an ungrounded part (conductive or dissipative) such as a machine or tool comes in contact with an ESD sensitive part. The solution to this problem is to simply ground the machine part, tools, etc…

The final source is charged device ESD. This type of ESD takes place when a part or device develops a charge and then comes in contact with a conductive item. Once the two parts touch there is a fast discharge which ultimately damages the ESD sensitive part. Ionizers are useful in this situation as they neutralize new charges and prevent build up of charges. Reducing movement of a part within the facility and having one common ground also helps combat charged device ESD.

Other things to keep in mind when protecting your ESD sensitive parts:

• Make sure your ESD bags and containers are not too old. Many materials lose their ESD protection over time.
• Have an ionizer? Make sure both emitters are working and make sure there is an equal balance of positive and negative ions.
• Store ESD sensitive parts in the appropriate containers. I know it seems like common sense but it’s important.

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