EPA zone

Electrostatic Discharge (ESD)

During direct contact between objects made of different materials, electrostatic charges are generated. The flow of charges between objects with different potentials is called Electrostatic Discharge (ESD). The process itself is also induced by an electrostatic field. We are unable to perceive the flow of charges, which does not mean it does not accompany us during everyday activities such as driving a car or going for a walk. The result of the charge flow is the generation of high-voltage levels, which can cause damage to components at any stage of production, testing, transportation, or use.

Safe production space

A safe production space for employees and for electronics devices is called EPA Zone (Electro-Static Protection Area). It is an area where the maximum electric field intensity is 100 V/cm. The flooring of the Electrostatic Protected Area (EPA) is lined with antistatic flooring, and the entrance and exit of the area are secured with gates and marked with boundary strips and labels. The flooring system is constructed with epoxy resin, which acts as an insulator. The floor is cleaned using specific cleaning agents. The EPA area is inspected to ensure compliance with requirements and is certified accordingly.

Proper humidity and temperature

Humidity and air temperature play a significant role in the EPA zone. Low humidity promotes the accumulation of electric charges. To address this issue, workstation or handheld ionizers are used. Their function is to disperse ions and neutralize hazardous charges.

Who is responsible for the proper functioning of the EPA zone?

The person responsible for ESD protection is the coordinator. They carry out their tasks by maintaining a record of all approved ESD protection devices and items, as well as conducting periodic measurements. With the support of the production manager, the ESD coordinator establishes procedures for safe employee behavior. The ESD coordinator also serves as an auditor during control audits, ensuring that ESD conditions specified by standards developed by the International Electrotechnical Commission (IEC) EN 61340-5-1:2009 and EN 61340-5-2:2002 are met.

ESD protection for employees

Protection against ESD's negative effects is provided by conductive, shielding, charge-dissipative, and insulating materials. Conductive materials aim to increase the speed of charge dissipation through the material to the ground. Common insulating materials include glass, air, and plastic, while examples of shielding materials are carbon and metals.

In electronic companies, personnel are continuously trained in ESD safety. The most critical element of personnel protection is grounding at the workstations. Workstation safety is ensured by specially designed two-layered table mats and wrist straps, which safely discharge charges from the body. The personnel present in the EPA zone should wear ESD protective clothing, gloves, special footwear, or shoe covers with conductive straps. Bringing personal belongings into the EPA zone is prohibited, and it is required to tie back long hair. All protective measures are subject to periodic inspection.

Protection of electronic components

The miniaturization and increased packaging density of electronic components contribute to their increased sensitivity to electrostatic discharges. Permanent damage to components leads to a failure to pass quality control tests and their withdrawal from production as non-compliant products. In other cases, improper voltage flow can result in high failure rates once the components leave the EPA zone, leading to costly product recalls.

Electronic components sensitive to electrostatic discharges are labeled with the ESDS (Electro-Static Discharge Sensitive Device) symbol. Special tools and even transport methods are used to minimize the risk of electrostatic discharges and surges. The line of defense is provided by shielding. Assembled PCBs are stored in ESD trays with covers equipped with a Faraday cage. Special conductive bags and foams are used during the transport of electronic components to prevent potential differences between the leads.