Reactive aqueous metal oxide sols as polishing slurries for low dielectric constant materials

摘要

An aqueous metal oxide sol slurry has been developed for removal of low dielectric constant materials. The slurry is formed directly in solution utilizing non-dehydrated chemically active metal oxide sols which are formed in a colloidal suspension or dispersion. The oxide sols have not undergone any subsequent drying and the particles are believed to be substantially spherical in structure, dimensionally stable and do not change shape over time. The sol particles are mechanically soft and heavily hydrated which reduces surface damage even in the case where soft polymer or porous dielectric films are polished. The sol particles are formed of a chemically active metal oxide material, or combinations thereof, or can be coated on chemically inactive oxide material such as silicon dioxide or can be coformed therewith. The oxide sols can include a bi-modal particle distribution. The slurry can be utilized in CMP processes, with or without conditioning.