There is always a need to have efficient and good static control equipments in any static electricity and Electrostatic Discharge (ESD) control program.

The most basic static control or ESD equipment is the surface resistance test kit.

This surface resistance meter measures surface to ground resistance or RTG for most of the static control products used within any ESD protected area (EPA) such as anti-static work surface mats, ESD carts, ESD smocks, ESD shoes, ESD flooring and ESD chairs.

There are two types of surface resistance meter available in the market place: the analogue and the digital type. For the digital type of surface resistance meter, the end user reads the measured resistance on the meter after testing is done. For the analogue type, the user is required to know how to read the meter in order to know the measured resistance value.

The digital type of surface resistance meter is definitely friendlier user then.

A typical surface resistance test kit consists of two five pound electrodes, two electrical test leads and a meter. For some test kits, two parallel probes are placed on the bottom of the meter to allow the surface resistivity measurement.

Most of the surface resistance test kits allow measured resistance in the range of 1×10E3 to 1×10E12 ohm at test voltages of 10V or 100V.

A good surface resistance meter would allow any user to measure surface resistance of his static control products with all the required information being given by the meter such as on ambient temperature and relative humidity of the testing environment.

However, an efficient surface resistance meter would be the one that allows user to measure the surface resistance very quickly at the set test voltage without the need to know how to read the measurement results on the meter.

One of the most efficient Surface resistance test kit that I had ever used was the Desco model 19775 surface resistance meters. The new models of surface resistance meter in the market are the good meters but they are not the efficient meters as the measured resistance value only appears after the ambient temperature and relative humidity of the environment are displayed. These meters slow down the checking process of the static control products inside the EPA especially when there are numbers of them to be measured periodically.

Where is the anti-static surface resistance test kit that I am looking for?

After many searches around the market, the efficient static control equipment for surface resistance measurement that I need is still within my reach. It is still out there. And that saves me ….. plenty of time.

How to avoid Fire at Gas Pump?
Many organisations spend lots and lots of money in their ESD control activities. All the money spent is used to buy wrist strap, wrist strap monitor, ionizer, static shielding bag just to name a few to protect their parts from being damaged by ESD.
There are many controls and awareness on ESD among organisations that build parts that are susceptible to ESD damage.
However, there is poor awareness among the public on the danger of static electricity especially at the gas pump.
According to Steve Fowler who is a static electricity expert says it happens more than you think, “We believe about 1,000 times a year in the U.S.”
To save your life and other person’s life, it is very important to know:

How does fire happen at the gas pump?
Fire breaks out at a gas pump due to static electricity.
When a person goes back to his vehicle, rubbing against the seat while sitting, talking to his children or taking his wallet, static charges are built up within his body due to his movements.
He transfers the static charges when he touches the gas pump nozzle, which generates a spark. The spark then ignites the gasoline vapours and fire breaks out.

Key points to remember when refuelling gas at Gas Station

• 1.      Turn off the engine of your vehicle
  
• 2.      Touching a metal surface away from the nozzle to discharge your static electricity before fuelling (Some gas pump stations provide Touching Pad for you to reduce your static electricity)
  
• 3.      Stay near your vehicle fuelling pint – DO NOT re-enter your vehicle
  
• 4.      Never smock, light matches or use lighters during refuelling
  
• 5.      Touch your vehicle or a metal surface to discharge any static electricity once refuelling is done before removing the nozzle
  

Warning:

1. If fire starts, LEAVE the nozzle in the vehicle.
2. Run away and safe your life.
   
3. Contact gas pump attendant immediately to shut down the pump.
   

Living in a cold and dry climate, I tend to experience lots of static shock.

I have got zapped whenever I touched the door knob. I almost burnt myself down when I refilled my car with gasoline at the gas station last weekend. I had fried many Integrated circuits and boards at working place and I never got the chance to pass my wrist strap testing.

Am I born a Static Man?

I wear a wool sweater with a leather jacket on top and with a rubber shoes. When it is too cold, I would put on gloves and cover my head with wool scarf.

What is wrong with me? Can anyone help me? I had asked many people around me about the solution for my problems.

Here is some of what they say:

1. Your skin might be too dry. Put on some lotion, it will help to reduce your dry skin problem.
2. Put on ESD smock at work place and ESD shoes. It would help to drain the static charge that accumulated on your body.
3. Place an ESD floor mat at your working place. The ESD shoes only work well when the ESD floor mat/floor is around.
4. Wear ESD boot/shoes even at outside your working place. The earth surface is conductive in nature and it would help to drain away the static charges.
5. Do not wear rubber glove. Get an ESD glove.
6. Remember to touch the car frame when you come out. That is to drain the static charges on your body.
7. Use ionizer to neutralize the static charge at your work place.

I felt thankful to the people whom had given the advice. Their insights had helped me to understand static electricity in one way or another.

Without them, I am lost.

 

ESD Association (ESDA) first established ANSI/ESD S20.20 standard in year 1999. ANSI/ESD S20.20 is a document that provides guidance to set up an ESD control program that protects ESD sensitive items with sensitivity threshold level of 100Volt or greater HBM model.  The emergence of this ANSI/ESD S20.20 has reduced the problems faced by many companies especially contract manufacturers that have many customers with different ESD plans. When it comes to static control, ANSI/ESD S20.20 standard allows organisation to speak a common language in all parts of the world.  Ron Gibson from Celectica Inc and John Kinnear from IBM are the well known ANSI/ESD S20.20 training gurus, actively training ISO 9000 registrars on this standard the following year. By end 2001, DNV, QMI and BSI were the ISO registrars available for certifying organisation on this standard. 

Celestica Inc was the first facility in the world to be audited and certified against ANSI/ESD S20.20 standard. This ANSI/ESD S20.20 standard can be applied in all activities that involved in handling ESD sensitive items. So far, there are many facilities that are already certified by the authorized ISO registrars including high tech-industry like Dongguan Wafer semiconductor. This ANSI/ESD S20.20 standard outlines the requirements that to be followed to ensure continuous ESD protection on the ESDS items produced or handled by the organisations. 

The ESD control program plan contains two sections: Administrative requirement section and Technical requirement section.  The Administrative section includes the Plan, Training and Compliance Verification. The Technical section covers requirements for Grounding/Bonding, Personnel grounding, Packaging, Protected area, Handling, Equipment and Marking.  Requirements and guidance provided by the ANSI/ESD S20.20 standard help organisations in setting up their ESD Control program. 

Some tailoring and adjustment to the requirements and the limits are required when handling more sensitive ESD products.  Implementing ANSI/ESD S20.20 program in a facility definitely contributes to the bottom line of the organisation. Products are not only protected from ESD damage, it will also increases customer confidence.  

 

As the electronic devices are getting smaller in geometry, they become more susceptible to ESD damage.  More and more ESD protective equipments and materials are manufactured and made available in the market place to help companies to combat their ESD problems. Some of the commonly used protective equipments and/or materials are wrist straps, heel straps, ESD shoes, ionizers, ESD mats, ESD smocks, ESD protective tote boxes and ESD static shielding bags.  All the ESD protective equipments or materials are designed either to ground/neutralize the static charges or to provide protection from harmful electrostatic field voltage.  ESD smocks are one of the key materials used to protect ESDS items from harmful electrostatic field voltage, which is generated from a wearer’s internal street clothing.  There a few types of ESD smock in the market. Most of them are either made of polyester/cotton or a mixture of polyester and cotton material with conductive fibres sewn in singular lines or crosschecked patterns. 

An ESD smock that is made of polyester with conductive fibres sewn in crosschecked patterns is the preferred choice over the cotton type or fabric with singular conductive lines.  The ESD smock with crosschecked patterns does not only provide better shielding effect from harmful electrostatic field voltage, it also gives better electrical resistance between panels of the ESD smock.  Static charges that sit around the conductive fibres on the ESD smock are drained to ground either through a grounding wire that comes with the ESD smock or through a contact between the ESD smock and the skin of a wearer.  The contact between the ESD smock and the skin of the wearer is achieved either by having an elastic band or a snap button at the wrist portion of the ESD smock.  The conductive fibres or threads that are sewn on the ESD smock are easily damaged by a strong laundry detergent or through ironing. 

Companies will have to set controls on the ESD smocks to ensure they last longer and provide the necessary protection to the ESD sensitive devices that are used in the production assembly lines. 

 

 

As we know Knowledge is Power, therefore it is important especially for those who deal with ESD in their work to improve their knowledge in ESD continuously.

There are many ways where ESD knowledge can be improved:

1. ESD Training : ESD training is available in many forms. Some include ESD computer based training whereby the Training material is in a CD-ROM or ESD Training that is available in the form of classes or seminars.
2. ESD book : Many books on ESD are available in the marketplace where immense ESD information can be obtained here.
3. ESD forum : At times, you can get all you are looking for in a forum. There are many professional and experienced people out there who can help you to get your questions answered or even solve your ESD problems. ESD forum is the cheapest way for getting information and improving your ESD knowledge.
4. ESD consultant : When it comes to the worse case where you still could not solve your ESD problems after trying so many means and ways, then the best way is to approach an ESD consultant.

Here are the recommended sources where you can get the ESD consultancy:

• Dangelmayer and Associates

- Trusted ESD Control programs since 1978. Provides auditing, training, R&D device/systems in EMI and ESD, failure analysis, S20.20 pre-certification assessments, Electrostatic attraction competency.

• Fowler and Associates

- Established in 1957. Provides consulting, training, testing, auditing, expert witness and forensic investigations for Electrostatics, ESD, RFI, Electrical, Electronics, Radiation Processing, Radiation Safety and packaging.

• Halperin and Associates

- The industry leader in static control for over 25 years. Provides training and seminar schedule, marketing and product development, ANSI/ESD S20.20 program design, material evaluation and testing, facility auditing and evaluation.

 

Nowadays almost everyone owns a computer at home. Computers have become a part of our lives: to access to news around the globe and information of any kind at anytime we like. Some people assemble computers to sell and some even open up and repair their own computers. There are few things that we should be aware of to prevent the computer parts from being damaged by electrostatic discharge or rather known as ESD. Major computer parts like motherboard, central processing unit (CPU) chip or microprocessor, random access memory (RAM) card, video card and hard disk drive are sensitive towards ESD damage.
As a precaution, we have to wear a wrist strap when working with these computer parts. The wrist strap must be snug against our skin to ensure a good connection for draining the static charges from our body. Connect an alligator clip to the banana plug of the other end of wrist strap ground cord. Connect the alligator clip to the computer chassis when working with the computer parts.
The computer is at the OFF state with the AC power cord of the computer remain attached to the power outlet or receptacle to provide ground path to drain the static charges. Another way is to connect the banana plug of your wrist strap to a ground adapter plug, for example, GAP-005 ground adapter plug. It is always advisable to set up a static protective workbench with a grounded ESD mat on the work surface to place all the sensitive computer parts. Besides taking the ESD precaution, we also need to handle especially the hard disk drive part with care as they are easily damaged by vibration and shock. When buying a new computer part like motherboard, hard disk drive, video card, RAM card or CPU microprocessor, we need to ensure the part is packaged inside the ESD protective bag, for example, shielding bag with an extra protection from vibration and shock for the hard disk drive part.

Electrostatic Discharge or ESD is going to receive more attention from industries in the future. Electronic chips are getting smaller and designed to work faster with more complex features. These make ESDS items more susceptible to ESD damage.  Without a proper ESD control in the manufacturing, more ESD sensitive items are easily damaged. This results in more products return, low yield, increasing operation cost and unsatisfied customers.  Quality product is important for any company to sustain in today’s competitive business world. Companies require proper manufacturing practices to compete and earn larger market share in the global business world. ESD problems can be controlled. A proper handling of ESDS items is one of the key principles to bring the problems under control. Here are the few examples:   

ESD S20.20-1999 Standard requires an employee to wear a wrist strap when handling ESDS items in a seated position. At times the employee does not snug the wrist strap band properly to his skin. This causes the employee ungrounded. Static charges that are built up within his body due to movements would pose a danger to the ESDS items. Technology is moving fast. A new wrist strap monitor which is battery operated is now available in the marketplace. This wrist strap monitor will give out a visual indicator and an alarm whenever a person is not properly grounded.  

Soldering iron that is used by an employee during the touch up work needs to be grounded.  The ESD Standard requires the tip to ground of the soldering iron to be not more than 20 ohm when in use. It requires a periodic check on the tip to ground of the soldering iron to ensure that it is at the same electric potential with the ESDS items, which are placed on a grounded ESD mat.  The ESD mat that acts as a work surface on the workbench must have an ability to drain static charges at a rate, which is not too fast or too slow.A two-layered rubber ESD Mat that is made from a top conductive layer and a bottom dissipative layer is the most recommended ESD mat. It provides a resistance to ground between 1×10E6 ohms to 1×10E9 ohm, which falls within the recommended resistance range of the ESD Standard. It is unavoidable not to have process insulator like connector plastic containers at workbenches. When this situation arises, use ionizers to neutralize any unwanted static charges on the insulators. Overhead ionizers, bench top ionizers and air gun blowers are the most commonly used ionizers at workbenches. Again companies have to check the functionality of these ionizers periodically. ESD standard recommends offset voltage of the ionizer not to be more than 50Volt. However the offset voltage of the ionizer needs a tighter limit when dealing with more sensitive parts.

Your customer may request your employee to wear gloves during handling of their products. What type of glove is suitable for use? Gloves with anti-static property like nitrile gloves or lint-free ESD gloves are the few types that would meet your needs.  

Ionizers are the heart of static control program in clean room environment.
Many insulative materials such as plastic, Teflon, ceramic and glass are widely used as part of the process materials.
Static charges build on these insulative materials when there is a contact and separation with other materials during the processing activities. Unlike the conductive material, static charges on the surface of the insulative materials cannot be drained away. There just stay there.
Charged insulative material can induce opposite charges on a neighbouring ESD sensitive part, which is placed within its electric field. Damage to the part is done when a person touch it in the presence of the electric field. Some ESD sensitive items, for example, reticles are damaged when present in the electric field.
ESD sensitive parts, for example, semiconductor wafer, that has static charges on its surface would attract particulate from the air and contaminate the wafer.
There are a few ways to remove or neutralize static charges on the insulative material.
Using an antistatic solution that is compatible to the environment (clean room compatible when used in clean room environment) or ionizers are the two common methods currently available to minimize static charges on the insulative materials.
Ionizers provide permanent solution when it comes to combat static charges on the insulative materials.  Neutralization of static charges occurs when ions produced by the ionizers are attracted to the opposite polarity of static charges on the material surfaces.
There are two common types of ionizers that are widely used. There are corona air ionizer and alpha nuclear ionizer.
Corona air ionizers themselves are divided into three types: AC corona ionizers, Steady state DC corona ionizers and pulsed DC corona ionizers.
Corona air ionizers apply high voltage to the sharp emitter points. The strong electric field would accelerate the free electrons that are present in the atmosphere to the positive emitter points. The fast moving electrons collide with the gas molecules and dislodge the weak bonded electrons from the molecules, giving rise to positive ions, which are then repelled, from the positive emitter points.
At the negative emitter points, the free electrons in the atmosphere are pushed away from the emitter points. These fast moving electrons collide with gas molecules and dislodge electrons from the molecules. These dislodged electrons are in the atmosphere for not long before they are captured by other neutral gas molecules and give rise to a flood of negative ions.
Corona air ionizers are not suitable for all applications. Depending on the type of emitter point material used, the ionizers tend to introduce particulate contaminants to the air. The ions balance for corona ionizers would never be zero.
For that reasons, alpha ionizers are the answer. Alpha ionizers are normally used in a volatile environment and in an environment where very sensitive ESD sensitive items are handled which require balanced ionizers.
Alpha ionizers use Polonium 210 radioactive source, which emit alpha particles.
The alpha particle collides with a gas molecule and dislodges an electron. The free electron is then captured by neighbouring neutral gas molecule and becomes a negative ion. A balance number of positive and negative ions are produced in the alpha nuclear ionization process.
There is a local government regulatory rules that need to be followed when alpha ionizers are used. Periodic annual renewal of the alpha nuclear source is also required to ensure proper functionality of the ionizers.
A Charge Plate Monitor (CPM) is commonly used to check the effectiveness of an ionizer.
Monitoring the balance ions (offset voltage) and discharge decay time would be able to tell whether the ionizer performs its intended function.
 

Type of ESD damage

Depending on the severity of the ESD damage, an ESD 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 ESD 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 ESD damage

There are three common sources/models of ESD Damage. There are: