Synthesis of Spherical-like Ceria Particle with PVP as Assistant Agent and Its CMP Performance on Shallow Trench Isolation

Abstract

Chemical Mechanical Polishing (CMP) has become a widely accepted global panarization technology. Abrasive is one of the key elements during CMP process. Du to its high selectivity, ceria particle is often used as abrasive in shallow trench isolation (STI) CMP slurries. But its irregular shape and agglomeration is not acceptable. In the present work, the spherical-like ceria nano-particles were successfully synthesized by homogeneous precipitation of ammonium cerium nitrate and urea, with Polyvinylpyrrolidone (PVP) as assistant agent. The precipitated ceria particles were characterized by means of XRD, FTIR, SEM and EDS as well as Zeta potential test. The results indicated that these nano-particles had a good dispersibility in water media without addition of any extra dispersing agent. Then, the CMP performance of these nano-particles on STI was investigated. The results indicated that they exhibited high removal selectivity (10.8:1) between silicon dioxide and silicon nitride without any additives.