Development of copper CMP slurry

Abstract

This paper presents a formulation of slurry for Cu CMP, in which colloidal silica (SiO/sub 2/) was used as the abrasive particles. Since Cu is chemically active we tried to planarize Cu by "soft friction" using colloidal silica (size of 20nm), with the selected oxidizer in which metal ions aren't involved, and organic amine is used as the complex agent. Silicon sol (size of 20nm) is softer than Al/sub 2/O/sub 3/, has no contamination, and better dispersity and suspension with little scratching. Moreover, adding non-metal ions to the chelate can compress contamination of metal ions and adsorption of particles, so that the surface is smooth and bright.