ESD in Electronics Manufacturing: What PCB Engineers Should Know

In printed circuit board manufacturing, electrostatic discharge (ESD) can be a real problem if unaccounted for. Thankfully, PCB contract manufacturers (CMs) use multiple processes and manufacturing techniques to ensure that PCBs don’t suffer from ESD events. Take a moment to consider the different problems with ESD in electronic manufacturing and methods to correct them.

The Dangers of ESD in Electronics Manufacturing

Many component failures arise due to problems with ESD during electronics assembly. Not only is ESD responsible for outright component failures, but often, the damage is so slight that it can cause component failures later on during their normal expected life cycle. In the case of an outright component failure, the damage will be instantaneous. A large enough ESD discharge can damage the internal circuitry of a component by melting metal or causing an oxide punch-through where a conductive path forms between the insulating layers.

Although these failures can cause many difficulties for manufacturing in that the part will require rework, the more insidious issues are ESD discharges at lower voltage levels. Lower levels of ESD will affect the metal and insulation of a part, but not to the point of complete failure. These issues are known as “latent defects” and can shorten the life of a device, causing it to malfunction later when the device is in use on a circuit board. As component sizes shrink, their internal circuitry becomes even more susceptible to ESD damage. Therefore, PCB contract manufacturers must exercise caution when handling sensitive devices.

Methods to Control ESD During Manufacturing

There are four areas that PCB contract manufacturers will concentrate on to protect sensitive components from ESD during manufacturing:

• Component identification – Although sensitive devices are pre-packaged by the manufacturer in static-controlled containers, the PCB CM still needs to identify which components are more sensitive than others and handle them appropriately. This step is essential not only for ESD but also for moisture-sensitive parts.
• Component handling – Once the components are in-house, the PCB CM needs to follow documented procedures for handling them. This process includes using them within designated ESD-protected areas of the manufacturing floor and ensuring that assembly technicians have the requisite training and preparation to work with these parts.
• Establish ESD-protected areas – Areas for working with ESD-sensitive parts must contain the correct tools and equipment to minimize the generation of static electricity. These areas require controls to ensure that only workers trained in ESD control methods and prepared with the proper equipment have access.
• Dissipate ESD – No matter what, the potential for ESD will never completely go away. Therefore, workers must use proper ESD dissipation methods. These include using grounded wrist straps, wearing ESD-safe clothing and gloves, using ESD-safe tools, and working on anti-static floor mats.

In addition to the steps above that a CM will take to control ESD in manufacturing a printed circuit board, there are also additional steps. The board requires a robust design to protect against the effects of ESD, including components that are more resistant to ESD with protective input circuitry. Also, after board manufacturing, the PCB needs a static-controlled container and handling by technicians trained in ESD control methods.

Your CM Prevents ESD for Improved Service Life

At VSE, we have built circuit boards for different technologies and industries for over forty years. As such, we have accumulated vast knowledge about ESD in electronic manufacturing and designed our ESD protection processes accordingly. Our tightly controlled component handling protects sensitive components from arrival to final assembly.