Liquid particle monitoring system utilizing aerosol metrology and data processing algorithm: chemical mechanical polishing slurry application

This study presents an aerosol‑metrology approach using an integrated atomizer–SMPS (A‑SMPS) to measure NVR‑subtracted hydrosol particle size distributions (HPSDs). Standard polystyrene latex (PSL) nanospheres and three chemical mechanical polishing (CMP) slurries (two silica-based and one ceria-based) were measured with the A-SMPS. A multi-stage algorithm converts the SMPS-measured aerosol particle size distribution (ASD) into an NVR-subtracted hydrosol particle size distribution by sequentially (i) removing non-volatile residues (NVRs) generated during aerosolization to yield the NVR-subtracted aerosol particle size distribution and (ii) applying an empirically derived calibration based on PSL references. Experimental results indicate that this approach yields consistent HPSDs across different dilution factors (DFs), effectively separating abrasive particle peaks from surfactant-induced NVR peaks. For the ceria and two silica slurries, the peak positions and amplitudes were nearly invariant across DFs confirming the robustness of the ASD-to-HPSD inversion and the accuracy of the DF-corrected original number concentrations. Integrating aerosol-based detection with the inversion process offers a precise and flexible strategy for quantifying ∼ 100 nm abrasive particles in CMP slurries, and enables accurate hydrosol characterization for semiconductor process optimization.