Unraveling Slurry Chemistry/Nanoparticle/Polymeric Membrane Adsorption Relevant to Cu Chemical Mechanical Planarization (CMP) Filtration Applications

Abstract

© The Author(s) 2019. Due to the emergence of sub-10 nm technologies, next generation slurries have continued to increase in complexity to meet stringent device performance demands. Prior to the chemical mechanical planarization (CMP) process, point-of-use filtration (POU) is implemented in order to limit particle aggregates and ultimately decrease surface defects. This study probes the non-covalent interactions at the interface of a fundamental Cu slurry and a polyamide and polypropylene-based membranes. Results indicate that independent of the membrane used, material removal rate (MRR) showed a subtle decrease as a result of filtration (time and ∆P), demonstrating that the synergistic balance between the nanoparticle and slurry additives is disrupted during the filtration process. Corrosion current measurements (Icorr) decreased by at least 85% post-filtration, indicating a rapid adsorption of glycine to the filter membrane. Regardless of the filter membrane, glycine adsorption was further validated using a modified electrochemical quartz crystal nanobalance (EQCN) technique. Since Cu-glycine complexes are integral in controlling MRR, a widely reported method of tracking ∗OH production was employed. Results show a decrease in the concentration of ∗OH, which in turn can be correlated to a decrease in the Cu-glycine complexes, altering the overall Cu MRR.