Application of electrospray-scanning mobility particle sizer for the measurement of sub-10 nm chemical mechanical planarization slurry abrasive size distribution

A scanning mobility particle sizer (SMPS) was used for measuring the size of a sub-10 nm chemical mechanical planarization slurry abrasive. An atomizer and an electrospray were used for aerosolization of slurry abrasives. It was difficult to measure the exact particle size distribution using the atomizer due to the agglomeration peak generated by the relatively large droplet size. However, the electrospray-SMPS (ES-SMPS) measurement result well matched with that of the transmission electron microscopy analysis without the agglomeration peak as ES is known to generate a relatively small droplet during aerosolization. The particle size distribution of the two sub-10 nm ceria slurries was measured using the ES-SMPS. To avoid the dispersion stability issue due to the pH change, pH adjustment was required when the sample was diluted.