(111) Faceted Ceria and Its Influence on STI CMP for Memory Devices Below 50 nm

Abstract

We investigated the effects of (111) faceted ceria nanoparticles on the removal rate of oxide films in shallow trench isolation (STI) chemical mechanical planarization (CMP). The X-ray diffraction peak ratio of (111) to (200) for the (111) faceted ceria particles synthesized by a flash-creation method was 4.08, while the ratio for polyhedral ceria synthesized by a solid-state displacement reaction was 2.65. The highest surface density of atoms in the (111) plane led to an increase in removal rates. Faceted ceria slurry yielded a higher oxide removal rate and greater selectivity than the polyhedral ceria slurry in STI CMP evaluation.