Shallow trench isolation polishing using mixed abrasive slurries

Abstract

Isolation of active areas, e.g., transistors, in integrated circuits and the like so that functioning of one active area does not interfere with neighboring ones, is provided by the shallow trench isolation technique followed by chemical-mechanical polishing with a mixed abrasive slurry consisting essentially of (a) relatively large, hard inorganic metal oxide particles having (b) relatively small, soft inorganic metal oxide particles adsorbed on the surface thereof so as to modify the effective charge of the slurry to provide more favorable selectivity of silicon dioxide to silicon nitride, the slurry having a pH below about 5.

Dependencies are inferred from the claim text.