Zeta Potential of CMP Slurries

Guest speaker Dr. David Fairhurst joins HORIBA Scientific to discuss the important role zeta potential (ZP) plays in the performance of CMP slurries. In this webinar we will first review and discuss the importance of the iso-electric point of metal-oxide polishing agents and the role of slurry pH and then we will examine the effect of slurry fluid chemistry using ZP measurements to characterize the chemically-modulated development of surface charge of such polishing agents during aqueous polishing.

Background: While particle size has been long recognized an important metric, the most fundamental and critical aspect of the CMP slurry system is the molecular interaction between the suspended particles and the medium at the interface. It is such an interaction, along with the particle–particle interactions, that determines the dynamic properties of the dispersion and strongly affect the performance of the slurry. In polishing, it is generally accepted that the removal rate is directly related to the availability of the surface hydroxyl groups on the abrasive particles. Thus, understanding the role of surface charge effects is important in optical finishing.   The zeta potential is a parameter (symbol ζ), which is related to the surface charge (vide the interfacial chemistry), a property that all materials possess, or acquire, when suspended in a fluid; ZP measurements have long been recognized as a surrogate function of particle surface chemistry.