Superior chemical-mechanical polishing performance of silica slurries made of surface-active siloxane/acrylic polymers

Abstract

Two new anionic polymers have been synthesized by opening the epoxide ring attached with polysiloxane (SHS) and polyacrylic (CHS) backbones with a comparable weight-average molecular weight range. The colloidal stability of the experimental silica slurries made of these polymers has been investigated and their performance in the chemical–mechanical polishing (CMP) has been studied. A nonionic polysiloxane copolymer (SHE) was also used as a cosurfactant. It was observed from surface tension and fluorescence studies that all these polymers transfer to the air–water interface before forming any aggregates and the ease of forming the aggregates is in the order CHS–SHE (1:1 blend) ≈ SHS–SHE (1:1 blend)>SHE>SHS>CHS. The apparent viscosity data and the scanning electron microscopy micrographs of the silica slurries indicate that all the polymers provide good colloidal stability over a wide range of concentrations. The superior CMP performance over commercial slurry is reported and the order of performance due to the presence of these polymers was also determined and is correlated with the dynamic contact-angle values. The results were interpreted in view of the hydrophilicity of the copolymers and their surface wetting ability.