Preparation of Irregular Silica Nanoparticles by the Polymer Templating for Chemical Mechanical Polishing of Sapphire Substrates

Irregular silica nanoparticles were prepared through polymer templating and their application on chemical mechanical polishing (CMP) of sapphire substrates was performed. Irregular silica nanoparticles were obtained by the chain structure of PEG200 and many oxygen functional groups. Silica seed particles can be rapidly coated through hydrogen bonding and also overlapped for two or more silica seed particles. The results show that the material removal rate of irregular silica nanoparticles increases by 58.7% compared to that of spherical silica nanoparticles. The surface roughness of the sapphire substrates measured by an Ambios Xi-100 surface profiler is 1.584 nm. Energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy revealed that some solid-state chemical reactions occurred during the CMP process. Possible mechanical effects of irregular silica nanoparticles in CMP process were also discussed.