Influence of the electrokinetic behaviors of abrasive ceria particles and the deposited plasma-enhanced tetraethylorthosilicate and chemically vapor deposited Si₃N₄ films in an aqueous medium on chemical mechanical planarization for shallow trench isolation

The effects of the electrokinetic behavior of abrasive ceria particles suspended in an aqueous medium and the deposited plasma-enhanced tetraethylorthosilicate (PETEOS) and chemical vapor deposition (CVD) Si₃N₄ films on chemical mechanical planarization (CMP) for shallow trench isolation were investigated. The colloidal characteristics of ceria slurries, such as their stability and surface potential, in acidic, neutral, and alkaline suspensions were examined to determine the correlation between the colloidal properties of ceria slurry and CMP performance. The surface potentials of the ceria particles and the PETEOS and CVD Si₃N₄ films in an aqueous suspending medium were dependent on the pH of the suspending medium. The differences in surface charges of ceria particles and the PETEOS and CVD Si₃N₄ films have a profound effect on the removal rate and oxide-to-nitride selectivity of CMP performance.