What Is ESD? Electrostatic Discharge Explained

Electrostatic discharge (ESD) causes a brief, high-energy current pulse. ESD is one of the top causes of hidden damage in electronics manufacturing, display production, and precision assembly.

In everyday life, an ESD event is the small shock you feel when you touch a metal door handle after walking across carpet. In electronics manufacturing, the same effect happens at smaller scales. Even a tiny discharge event carries enough energy to damage a semiconductor device permanently. Controlling ESD before it reaches your components protects both quality and production yield.

What Causes Static Electricity and ESD?

Static electricity builds through the triboelectric effect. This effect causes charge separation when two materials touch and then separate.

Walking across carpet, unwrapping plastic packaging, and moving film across a conveyor roller all generate static electricity. Charged objects in a dry factory hold far more electrostatic energy than in a humid environment. ESD events are more frequent in air-conditioned spaces below 40% relative humidity.

Common sources of static charge include human bodies on non-conductive flooring, plastic bags and foam packaging, moving film on conveyor lines, and standard plastic work surfaces. Any non-conductive surface that contacts a moving object is a potential source of harmful electrostatic charge.

How Much Voltage Does an ESD Event Involve?

Static charge on common charged objects in a factory reaches high voltages. A person walking on synthetic carpet may carry 35,000V. Working at a vinyl bench generates 6,000V. Picking up a plastic bag generates up to 20,000V.

Modern CMOS devices fail from an electrostatic discharge event of 100–200V. This voltage is well below what humans can feel. Discharges occurring at voltages you cannot sense destroy the components you handle. This mismatch between human perception and device sensitivity is the central challenge of ESD control.

ESD Discharge Models

Two models describe how electrostatic discharge reaches a sensitive component.

The Human Body Model (HBM) covers discharges occurring when a charged person touches a component. The human body stores static electricity at 2,000–35,000V depending on footwear, flooring, and humidity. HBM events discharge over about 150 nanoseconds. HBM is the most common ESD scenario in assembly environments.

The Charged Device Model (CDM) covers discharges occurring when the device itself is charged and contacts a grounded surface. CDM events discharge in under one nanosecond. This speed makes them destructive to high-speed integrated circuits. CDM sensitivity worsens as transistor geometries shrink and gate oxide layers become thinner.

How ESD Damages Electronic Components

ESD damage takes two forms: catastrophic failure and latent damage.

Catastrophic failure means the component fails right away. An ESD event burns a junction or ruptures gate oxide. Electrical testing catches this failure at the production stage. The result is direct scrap or rework cost.

Latent damage is more dangerous. The component weakens from an ESD event but passes testing. It then fails in the field — hours, days, or weeks after shipment. Industry data shows that latent ESD damage accounts for a large share of field return failures. Standard functional testing cannot detect latent damage.

Both failure modes share one root cause: discharges occurring through a device structure that cannot handle the current. Preventing ESD events before they reach the device is the only reliable solution.

Industries Most Affected by Electrostatic Discharge

PCB and SMT manufacturing faces continuous ESD risk. Components are handled repeatedly during printing, placement, reflow, and inspection. Static electricity on plastic carriers and feeders adds risk at every stage of the line.

Semiconductor fabrication and test environments handle bare die and packaged ICs at advanced nodes. At geometries below 7nm, sub-100V discharge events cause measurable damage. Cleanrooms use ionization to neutralize static electricity on wafers and handling equipment at every process step.

Display panel manufacturing is vulnerable because static electricity on polarizer films attracts airborne particles. These particles cause bright-spot or dark-spot defects visible after final inspection. ESD into thin-film transistor arrays damages pixels and creates visible defects that cannot be reworked.

Printing, packaging, and plastics industries face static electricity as a process problem rather than a component damage issue. Charged objects cause sheet misfeeds, ink misting, label errors, and surface contamination. The cost appears as downtime and waste.

How to Prevent ESD Damage

Effective ESD control follows three principles: ground what you can ground, ionize what you cannot ground, and keep all sensitive parts inside an ESD protected area (EPA).

Grounding connects all conductive objects — people, equipment, and tools — to a common ground point. This prevents static electricity from building between charged objects. A calibrated wrist strap is the most important item for any operator who handles sensitive components. Surface resistance of work surfaces and flooring must fall within dissipative or conductive ranges per ANSI/ESD S20.20.

Ionization handles surfaces that cannot be grounded. Plastic films, PCB laminates, and glass panels accumulate static electricity with no path to ground. Industrial static eliminators and ionizing bars emit balanced positive and negative ions that neutralize charge on insulating surfaces. Ionization reduces residual charge to below ±100V on standard lines and below ±20V on precision production lines where display panels and optical films are processed.

ESD-safe materials slow charge buildup on surfaces that operators and components contact. Dissipative work surfaces, static-shielding bags, and conductive floor coverings reduce the size of any discharge event that occurs. Replace standard plastic bins, bags, and work surfaces with ESD-rated alternatives throughout the EPA.

ESD Standards

The main ESD control standard for electronics manufacturing is ANSI/ESD S20.20. The international version is IEC 61340-5-1. Both standards set requirements for ESD protected areas, grounding, ionization, packaging, and auditing. Compliance is required by many customers in automotive, medical, and aerospace supply chains.

Regular audits keep the program effective over time. Wrist strap checks, surface resistance measurements, and ionizer performance verification are the core audit activities. Clean emitter needles on ionizing bars every four to twelve weeks to maintain rated neutralization performance.

DGSDK Static Elimination Products for ESD Control

DGSDK manufactures industrial static eliminators for electronics, display, and precision manufacturing environments.

The ST-G Intelligent Static Elimination Bar uses DC pulsed ionization with real-time balance monitoring and self-diagnostic alerts. It is designed for inline use on display panel, PCB, and optical film production lines.

The ST-E Intelligent Ion Rod is a compact ionizer for integration inside machines and enclosures. The ST-S200 Mini Ionizer Fan and ST101A Desktop Ion Fan provide workstation-level ESD control for assembly and inspection areas.

Contact us to discuss your ESD control needs and get a product recommendation for your process.