FIELD: chemistry.
SUBSTANCE: invention relates to a novel aqueous polishing composition for polishing semiconductor substrates having polysilicon and silicon oxide dielectric films, and optionally having silicon nitride films. Said aqueous polishing composition contains (A) at least one type of abrasive particles, (B) 0.001-5.0 wt % of at least one water-soluble polymer, (C) at least one anionic phosphate dispersant. The abrasive particles (A) contain or consist of cerium dioxide, are positively charged during dispersion in an aqueous medium, are free of component (C) and have pH in the range of 3-9, which is confirmed by electrophoretic mobility. Component (B) is at least one water-soluble polymer selected from a group consisting of straight and branched alkylene oxide homopolymers and copolymers. The invention also relates to a method of polishing substrates for electrical, mechanical and optical devices using said aqueous polishing composition.
EFFECT: disclosed composition has considerably improved oxide/polysilicon selectivity and enables to obtain polished plates having excellent global and local flatness.
13 cl, 6 tbl, 9 ex
