Evaluation of oxide chemical mechanical polishing performance of polystyrene coated ceria hybrid abrasives

摘要

The spherical polystyrene (PS) coated ceria composite particles with different PS core size were synthesized by an in situ chemical precipitation method. Chemical mechanical polishing (CMP) of silicon dioxide film was performed using the obtained core/shell structured PS/ceria hybrid abrasives and conventional solid ceria abrasives. Four different abrasive systems were tested in the oxide-CMP process and their performances thoroughly evaluated in terms of material removal rate (MRR) and surface roughness. The aim of this work was to explore the effect of core size on oxide-CMP behavior of PS/ceria hybrid abrasives. As confirmed by atomic force microscopy, fewer scratches were detected for the composites by comparison with solid ceria abrasives. For the PS/ceria hybrids with a comparable shell thickness (ca. 10 nm), the MRR increased with the PS core size at the expense of the surface roughness after CMP. The lowest root-mean-square (RMS) roughness (0.19 nm) was achieved for the PS/ceria hybrids with the smallest PS cores (ca. 120 nm), while the highest MRR (195 nm/min) was obtained for the hybrids with the largest cores (ca. 260 nm). This work presents our effort to explore the relationship between the microstruc-tures and the polishing performances of the core/shell structured PS/ceria hybrid abrasives in order to optimize the oxide-CMP performance.