Abstract: The invention relates to a chemical-mechanical polishing composition comprising (a) a first abrasive comprising cationically modified colloidal silica particles, (b) a second abrasive having a Mohs hardness of about 5.5 or more, (c) a cationic polymer, (d) an iron containing activator, (e) an oxidizing agent, and (f) water. The invention also relates to a method of chemically mechanically polishing a substrate, especially a substrate comprising tungsten and barrier layers (e.g., nitrides), with the polishing composition.

Abstract: The invention relates to a chemical-mechanical polishing composition comprising (a) a first abrasive comprising cationically modified colloidal silica particles, (b) a second abrasive having a Mohs hardness of about 5.5 or more, (c) a cationic polymer, (d) an iron containing activator, (e) an oxidizing agent, and (f) water. The invention also relates to a method of chemically mechanically polishing a substrate, especially a substrate comprising tungsten and barrier layers (e.g., nitrides), with the polishing composition.

Abstract: The invention provides a method of chemically-mechanically polishing a substrate comprising providing a substrate comprising a tungsten layer on a surface of the substrate and a silicon oxide layer on a surface of the substrate, providing a chemical-mechanical polishing composition comprising a tungsten layer and a silicon oxide layer using a chemical-mechanical polishing composition comprising a) surface-modified colloidal silica particles, comprising a negatively-charged group on the surface of the particles, wherein the surface-modified colloidal silica particles have a negative charge, a particle size of about 90 nm to about 350 nm, and a zeta potential of about ?20 mV to about ?70 mV at a pH of about 2, b) an iron compound, c) a stabilizing agent, and d) an aqueous carrier, and contacting the substrate with a polishing pad and the chemical mechanical polishing composition to polish the substrate.

Abstract: A chemical mechanical polishing composition for polishing a substrate having a tungsten layer includes a water based liquid carrier, abrasive particles dispersed in the liquid carrier, an iron containing accelerator, and a cationic polymer having an amino acid monomer. A method for chemical mechanical polishing a substrate including a tungsten layer includes contacting the substrate with the above-described polishing composition, moving the polishing composition relative to the substrate, and abrading the substrate to remove a portion of the tungsten from the substrate and thereby polish the substrate.