What is Static Electricity ?
Static electricity is an electrical charge at
rest created mainly by friction and separation causing an imbalance
of electrons. The magnitude of the static electricity depends
greatly on the type of material, speed of separation, contact
pressure, relative humidity of the environment, etc.
What is Electrostatic Discharge ( ESD
It is the sudden transfer ( discharge ) of static
electricity from one object to another. It is a micropark.
What problems Static Charge have to all
of us ?
In our daily activities, a person may feel shock
if the electrostatic discharge is 3000 volts or more. However,
modern electronic components such as IC chips cannot even withstand
charges of less than 500 volts causing it to be damaged without
noticing or realising the consequences. As technology is fast
catching up, an electronic component becomes even more sensitive
to the slightest amount of electrostatic discharge.
This have led us to realised how critical ESD
is to us in our modern society causing many companies to invest
substantially in such critical area to protect the sensitive components.
How Static Charge Is Generated ?
Triboelctrification is the charge that generated when two kind
of material come into contact and then separated. These two objects
became chaarged by gained electrons from the other. The magnitude
and polarity of the chrages depends upon the characteristics of
the two materials and affected by several factors like suface
condition, size of contact aarea, speed of separation and humidity.
Static charge on an object create an electrostatic field that
extend to surrounding can induce the charge on the object that
place nearby and caused them to become charged. Once it come to
contact to the ungrounded ESD sensitive devices, the amount of
unbalance charges will immediately transfer which cause the device
What Are The Solution To ESD ?
Virtually it is impossible to completely eliminate
ESD in the production environment. We can minimise the problem
This eliminates static charges in building up
rapidly. Grounding drains all static charge bulits up instantly,
making it the most common option used in the electronic industry.
Grounding includes personnel grounding devices such as wrist strap
and workstation grounding deviced such as ESD chair.
This method eliminates static charge through ionization.
In this method, ions are created artificially to neutralise charges
on both insulators and isolated conductors. However, neutralisation
through ionization should go parallel with grounding as it only
reduces the probability of an ESD event occuring.
Protect by isolating electronics components from
charged objects, fields, and insulator transportation. Using the
Faraday Cage concept, this concept emphasize that static charges
cannot penetrate conductive material.
The best solution to an ESD problem is prevention
and only you can prevent this from happening. The person in charge
should be aware of event ESD could happen, undestand the application
of ESD and ensure ESD DOES NOT happen. Training should be carried
out to ensure everyone is knowledgeable of ESD awareness in ESD
- sensitive areas followed by enforcement.
However, the ultiumate responsibility lies with
everyone and this makes everything possible.
ESD Material Classification.
1. Conductive ( 10e3 - 10e4 ) - good shielding,
allow charges to drains quickly, eliminate charges build-up.
2. Antistatic ( 10e5 - 10e11 )- Drains a charge
to ground moderately, minimal shielding, minimizes charge build-up.
3. Insulative ( 10e12 - ) - unable to drain a
charge to ground. Static charge bulidup remains on the insulators.
Static Electricity always exists
In today's workplace, the life and reliability
of modern semiconductors require an environment where static electricity
is continuously and totally drained to ground. Therefore, an Electrostatic
Protected Area ( E.P.A ) must be established at all stages of
receipt, storage, assmbly test and transport of electronic devices.