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US 6,676,719 B2Granted
Aqueous dispersion, a process for the preparation and the use thereof
AssigneeDegussa AG
InventorsWolfgang Lortz, Christoph Batz-Sohn, Helmut Mangold, Gabriele Perlet, Werner Will
Life of this patent
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Abstract
A pyrogenic process is used to prepare alkali-doped silica particles. Particles produced by this process exhibit homogeneous doping, reduced agglomeration, greater stability and higher removal rates. Aqueous dispersions containing alkali-doped pyrogenic silica with average particle size less than 100 nm are used for polishing surfaces (CMP).
Claims13
An aqueous dispersion of an alkali-doped silica, comprising:
- an aqueous dispersion of particles of alkali-doped silica having a particle size less than 100 nm from which the alkali dopant does not become mechanically detached as the dispersion is prepared in a high pressure homogenizer, said alkali-doped silica having been produced pyrogenically while being doped with an alkali containing aerosol, said silica comprising secondary particles having an average particle diameter of less than 100 nm and primary particles having a ratio dn/da of an arithmetic mean of a number distribution dn and an arithmetic mean of a surface distribution da of at least 0.7.
Dependencies are inferred from the claim text.