Development of a single particle sizing system for monitoring abrasive particles in chemical mechanical polishing process

A particle sizer was developed for real-time monitoring of suspended particles in chemical mechanical polishing (CMP) slurries to prevent any damage caused by coarse particles in the CMP process. Laser-induced light scattering from individual particles was utilized to monitor the concentration and size distribution of suspended particles in the CMP slurries, because monitoring is crucial for achieving higher than 80 % of chip yields by controlling the slurries. The particle sizer, Termed as PrimeSizer_SM Micro, consists of an integrated fluid system and optical sensing component. The PrimeSizer_SM Micro was calibrated using commercially available standard polystyrene-latex (PSL) particles with sizes in the range of 0.15–0.5 µm. Performance was evaluated in Terms of the PSL particle size distribution. Two types of CMP slurries, containing silica and ceria particles, were analyzed using the PrimeSizer_SM Micro. The results revealed the size distributions and concentrations of the CMP slurries.