| abstract |
The present invention provides aqueous chemical mechanical planarization (CMP) polishing compositions have excellent heat aging and shelf stability in the form of concentrates comprising a mixture of a compound containing two quaternary ammonium groups, such as hexabutyl C 1 n-C 8 nalkanediammonium dihydroxides or salts thereof, preferably N,N,N,N’,N’,N’-hexabutyl-1,4-butanediammonium dihydroxide (HBBAH), and aminosilane group containing silica particles in the amount of from 1 to 30 wt.% or, preferably, from 15 to 22 wt.%, as solids based on the total weight of the composition, the composition having a pH ranging from 3 to 5 or, preferably, from 3.5 to 4.5 wherein the composition is stable against visible precipitation or sedimentation at a 15 wt.% solids content after heat aging at a temperature of 45 ℃ for at least 6 days. |