Defects & Troubleshooting
Surface Contamination & Cleaning Issues
How contamination and improper cleaning degrade ESD performance and how to fix it.
Surface contamination is one of the most common—and overlooked—causes of ESD failure. Oils, residues, dust, and cleaning agents can dramatically change surface resistance, leading to inconsistent measurements and unexpected ESD events.
Types of contamination affecting ESD surfaces
- Skin oils: transferred through handling and foot traffic
- Dust and particulates: build up in dry environments
- Process residues: fluxes, adhesives, release agents
- Cleaning residues: soaps, detergents, waxes, surfactants
Even thin, invisible layers can significantly alter electrical behaviour.
How contamination affects ESD performance
- Increases surface resistance
- Creates uneven or patchy conductivity
- Introduces humidity dependence
- Causes inconsistent or unstable test results
In some cases, contamination can temporarily improve conductivity, masking underlying problems until conditions change.
Cleaning-related failure modes
- Use of household or industrial detergents
- Application of waxes or polishing agents
- Over-wetting or aggressive scrubbing
- Incompatible solvents damaging surface chemistry
Many cleaning products leave residues specifically designed to improve appearance, which directly conflicts with ESD requirements.
How to diagnose contamination issues
- Compare resistance before and after cleaning
- Inspect high-touch and high-traffic areas
- Test freshly cleaned versus aged surfaces
- Review cleaning agents and schedules
Corrective and preventive actions
- Use ESD-compatible, residue-free cleaners
- Define approved cleaning procedures
- Train personnel on ESD-safe maintenance
- Increase verification testing after cleaning
- Select surfaces with stable intrinsic conductivity
- Surface contamination is a leading cause of ESD instability.
- Cleaning can either restore or destroy ESD performance.
- Residues often cause more problems than visible dirt.
- Controlled cleaning procedures are essential for compliance.