Measurement of Particle Concentrations in Central Chemical Delivery Systems

This article evaluates recently developed high sensitivity optical particle counters for measuring particle concentrations in high purity semiconductor process chemicals. The results indicate that use of these low sampling rate counters is appropriate for obtaining accurate measurements. The results also indicate that particles in these chemicals may come from two sources: small particles that pass through the filters used to purify the chemicals and larger particles that originate at or downstream of the filter.