Probing the Role of Slurry Chemistry on Nanoparticle-Media Adsorption Relevant to Cu CMP Filtration Applications

Abstract

As the complexity of nanoparticle dispersions used in next-generation CMP slurries increases to meet stringent performance demands, it is necessary to develop polymeric filtration media that capture rouge particles in order to reduce overall surface defectivity without sacrificing planarization efficiency. Therefore, it is essential to probe the molecular level interactions at the nanoparticle/slurry chemistry/polymer filtration media interface and in turn correlate this to the key performance metrics such as substrate removal rate, post CMP defects, planarization efficiency. More specifically, simulated Cu CMP slurries with a wide range of film formation chemistries for performance control were evaluated with respect to the filterability through various polymeric filtration media. It was determined that a synergy exists between the structure of the additive (small organic molecule vs. surfactant-like additive) and the filter medias ability to regulate the dynamic adsorption processes of the slurry nanoparticles. Utilizing atomic force microscopy (AFM), electrochemical quartz crystal nanobalance (EQCN), modified ATR-IR spectroscopy, and in-situ rotating disk electrode corrosion measurements the static and dynamic nanoparticle binding mechanisms can be determined and correlated to the filterability studies. Furthermore, monitoring the pre/post filtration zeta potential and particle size distributions, bulk copper removal rate, and corrosion current as a function of filtration pressure, the role of filtration media slurry chemistry health can be surveyed on CMP performance based scale.