Preparation of Composite Spherical Alumina Nanoparticles and Study on their CMP Performance

The properties of abrasives have great influences on the surface qualities of glass substrate, hard disk, etc [1] , during the chemical mechanical planarization (CMP) process. α-Al 2 O 3 particles, as one of the most widely used abrasives in CMP slurries, often cause great surface defects because of its high hardness and unfeasible control of agglomeration during the synthesizing process [2,3] . In this paper, spherical nanocomposite alumina powders with particle sizes of 10-50 nm were prepared, via a homogeneous precipitation method. The structures and surface morphologies of the alumina nanopowders were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM). The results showed that the nanopowders composed of both alpha and theta phase alumina, which had a small particle size and narrow size distributions. The CMP investigations performed on glass substrate showed that the nanocomposite alumina abrasives exhibited a better surface planarization performance than the pure single alpha phase Al2O3 nanopowders, with lower surface roughnesses and less scratches after CMP process. The results indicated that the current processing for the synthesis of nanocomposite Al 2 O 3 powders were of great potentials for practical applications of Al 2 O 3 based abrasives.