Monitoring Agglomeration in CMP Slurries with Holographic Video Microscopy
Holograms of nanoparticle agglomerates can be analyzed with the theory of light scattering to obtain information about the agglomerates’ size, refractive indexes and morphology within their host nanoparticle slurry. This technique can be used to measure the concentration of agglomerates in precision nanoparticle slurries, to distinguish dense compact agglomerates from transient branch agglomerates. and to differentiate agglomerates from other contaminants, such as emulsion droplets and polishing debris. Furthermore, this technique, unique ability to study slurries undiluted, can be used to monitor agglomeration behavior of slurries under different stress conditions. This is the ideal tool to study agglomeration in commercial slurries during formulation, preparation, transportation, and applications in CMP slurries.