• • • SAFETY IN ENGINEERING • • •


ESD Protected Area: Electronics manufacturing facilities hold numerous potential ESD sources


Shocking Truth: How ESD threatens PCB


reliability and proven strategies to combat It By Elizabeth Norwood, Senior Chemist at MicroCare LLC


n PCB manufacturing, electrostatic discharge (ESD) presents a persistent challenge. When static electricity suddenly discharges across a PCB, it can compromise sensitive electronic components, leading to immediate failures or defects that appear later in a product’s lifecycle. ESD is responsible for a substantial percentage of PCB failures, and the costs associated with these failures, from rework to warranty claims, can be significant. The impact is not only financial, but also affects product reliability and, ultimately, a manufacturer’s reputation.


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Effective ESD control is, therefore, essential throughout the production process. Manufacturers can significantly reduce the risk of ESD damage by implementing cleaning practices and using specialised tools to end static build-up and contamination. This approach helps protect sensitive components and supports the production of reliable, high-quality PCBs that meet the rigorous demands of today’s electronics industry.


The Impact of ESD on PCB Reliability


Electrostatic discharge occurs when objects with different charges come into contact, rapidly transferring electrons as the charges equalise. This sudden release of energy, though often invisible, can damage sensitive PCB components, resulting in immediate, catastrophic failure or latent damage that only appears later.


Catastrophic ESD damage typically makes the component unusable, and this damage is often


detected during initial testing or inspection, allowing for replacement or rework. Latent ESD damage, however, is far more concerning, as it does not immediately affect functionality and can go undetected through testing. Latent damage can lead to intermittent failures and shortened lifespans in the field, making it difficult for manufacturers to trace the problem back to ESD. As such, latent ESD failures are often the most costly, damaging brand reputation and driving up warranty claims. Electronics manufacturing facilities hold numerous potential ESD sources. Common culprits include workers who naturally accumulate static charges throughout the day, ungrounded equipment, machinery and even seemingly innocuous items like plastic cups or certain materials near workstations. Environmental factors like humidity and temperature worsen these risks further by allowing static to accumulate more readily. Managing ESD, therefore, requires a multi-faceted approach that includes both environmental control and specific ESD-safe handling and cleaning protocols.


Cleaning to Prevent ESD To prevent ESD, PCB manufacturers should use a range of strategies, including cleaning protocols. These protocols have two purposes: removing contamination and dissipating static. ESD-safe cleaning fluids and tools are designed to reduce the risk of static build-up and ensure that contaminants such as oils, fingerprints, and dust are effectively removed.


20 ELECTRICAL ENGINEERING • DECEMBER/JANUARY 2025


Static-dissipative wipes play a crucial role in the cleaning process, these high-quality, pre-saturated wipes are designed to clean surfaces, tools and PCBs while dissipating static charges. ESD-reducing cleaning wipes effectively remove contaminants such as grease, oil and fingerprints without leaving lint, residue or static charges behind. However, it’s important to ensure these wipes contain a low alcohol level. While alcohol-based solutions are a popular cleaning agent, they are non-conductive, meaning they don’t contribute to dissipating static electricity. In fact, alcohol-based cleaners can dry out work surfaces, causing fissures and brittleness, which may increase static build-up.


The ideal ESD cleaning wipe should clean effectively and neutralise static charges, preventing potential ESD risks. Therefore, it is important to use wipes specifically formulated with ESD dissipative qualities.


Wipes: ESD-reducing cleaning wipes effectively remove contaminants such as grease, oil, and fingerprints without leaving lint, residue, or static charges behind


electricalengineeringmagazine.co.uk


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