Prevent static method

This article describes, in order to effectively combat and prevent electrostatic discharge (ESD, electrostatic discharge), must be the right way to use the correct equipment. As a series of strong loop ESD prevention, monitoring and ion devices can now ESD as a process control problem.

Electrostatic discharge (ESD) is the electronic circuit board assembly and damage to components of a familiar source of underestimation. It affects every manufacturer, without any of its size. While many people think they are in an ESD safe environment to produce products, but in fact, ESD-related damage continues to bring the world's electronics manufacturing industry costs billions of dollars each year.

What is ESD? Electrostatic discharge (ESD) is defined as, to or from the original has been static (fixed) charge (electron deficiency or excess) discharge (electron flow). Charge under two conditions are stable:

1 When it is "trapped in a" conductive but electrically insulated object, such as a metal with a plastic handle screwdriver. 2 when it is staying in an insulating surface (such as plastics), can not flow in the above.

However, if charged with a sufficiently high electrical insulation of the conductors (screwdriver) have opposite electric potential near the IC (IC), the charge "jumper", caused electrostatic discharge (ESD).

With high strength ESD occurs very rapidly, generally produce enough heat to melt the semiconductor chip's internal circuitry, the electron microscope look like bullet kid blow out, causing immediate and irreversible damage. More serious is that this harm is only one tenth of the situation bad enough to cause the entire test in the final component failure. The other 90% of cases, ESD damage caused only part of the downgrade - means that components can be damaged unaware through final testing, but only in the delivery to the customer site after premature failure. The result is the most damaged reputation of a manufacturer to correct any manufacturing defect where most of the consideration paid.

However, the main difficulty controlling ESD is that it is not visible, but can reach the point of damaging the electronic components. Produce can hear "tick" sound of the discharge requires considerable accumulation of approximately 2000 volts larger charge, whereas 3000 volts can feel like a small electric shock, 5,000 volts can see the sparks.

For example, as a complementary metal oxide semiconductor (CMOS, complementary metal oxide semiconductor) or electrical programmable read only memory (EPROM, electricall programmable read-only memory) of these common elements, SPI lcds respectively, and 100 is only 250 volts volts potential difference in ESD destruction, but more and more sensitive modern components, including the Pentium processor, as long as 5 volts can be destroyed.

The problem is caused by damage to the daily activities of the composite together. For example, from the factory floor through the vinyl on the floor surface and the friction between the shoes. The result is a pure charged object, accumulation of 3 to 2000 volts of charge depends on the local humidity of the air is quite.

Even workers stage formed by the natural movement of the friction can produce 400 to 6000 volts. If you open or packaging foam box or bubble bag PCB period, the workers have been processed insulator, Graphic LCD Display then the workers' accumulated net charge of the body surface can reach about 26,000 volts.

Therefore, as the main ESD damage sources all incoming ESD protection zone (EPA, electrostatic protected area) staff must be grounded to prevent any charge accumulation, and all surfaces should be grounded to maintain all things are in the same electric potential, to prevent ESD occurs.