ESD Damage
By LearnESD.com Team

Type of damage

Depending on the severity of the damage, an sensitive item can either be upset, wounded or experience a total failure.

Upset failures

An upset failure or intermittent failure is usually involving a temporary malfunction of equipment with loss of information and functions. A reset is required to resume the operation of the equipment. No apparent hardware damage occurs during this failure.

Latent failures

An ESDS item experiences a latent failure or is said to be wounded when the damages is marginal. This defect is very difficult to detect and most of the time the ESDS item still pass the final testing.

Total failures

A total failure or catastrophic failure occurs when an ESDS item is damaged to a point where it is no longer functioning. This failure is easily screened out through a tester.

Sources/Models of damage

There are three common sources/models of Damage.
There are:
1] Human Body Model ESD
2] Machine Model ESD
3] Charge Device Model ESD

Human Body Model ESD

Human Body Model causes the most failures.
It occurs when a human transfers the static charges from his body into the ESDS item. (E.g. during handling)
We need to ground ourselves either through a wrist strap or an shoe to prevent Human Body Model damage.

Machine Model ESD

When static charges that are present on an ungrounded conductive or dissipative part of a machine are transferred into an ESDS item, Machine Model event is said to occur.
We need to ground all the conductive and dissipative part of a machine to prevent the ESDS item from being damaged by the Machine Model ESD.

Charge Device Model ESD

Charge Device Model can be divided into two common types:
1] Charged Package Model
2] Field Induced Model

This Model basically represents event that takes place when electrostatic charges are transferred from a charged ESDS item into another object with a lower electric potential.

Charged Package Model

An ESDS item tribocharges when it slides down a plastic tube.
The static charges discharge from its body into a conductive container and an zapping takes place.
This event is called a Charged Package Model ESD.

Field Induced Model

When an ESDS item, for example an IC, is in an external electric field from a negatively charged object, it will be induced with positive charges facing the charged object while negative charges on the other side of the IC.
When a grounded person touches the IC, an event will occur.
Another event takes place when a grounded person removes it away from the negatively charged object.
This is an example of a Field Induced Model ESD.




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