Silica standards provide a materially different challenge from PSL.
The refractive response, density, surface chemistry and handling behavior can make silica appropriate for process-specific contamination studies.
When silica may be preferred
Silica can be selected where the process challenge or optical response should be more representative of inorganic contamination than PSL. The decision should be based on the study and inspection method.
Control dispersion and aggregation
Silica particles can behave differently in suspension and during deposition. Define dispersion quality, nominal size, concentration, deposition procedure and verification.
Characterize the baseline
Inspect and document the wafer before the challenge. Background defects, haze and handling marks can distort the result.
Certificate expectations
Require particle identification, nominal size, lot, deposition information, traceability statement when applicable, wafer identification and handling limitations.
Need help matching equipment to the study?
Applied Physics can review the airflow area, test objective, desired visibility, operating duration and deployment constraints.
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