Chemical Mechanical Polishing (CMP) of Fused Silica (FS) Using Ceria Slurry Recycling

Due to its high optical permeability, excellent high temperature resistance, and chemical inertness, fused silica (FS) has been widely used in astronomical telescopes, laser systems, and optical communication. Based on the smooth surface polishing of fused silica using ceria slurry, the variations of polishing performance of fused silica in the recycling polishing were studied. Meanwhile, the variations of the ceria slurry characteristics in chemical mechanical polishing (CMP) of fused silica were investigated. The variations of the average size and the morphology of the abrasive ceria particles were measured. X-Ray photoelectron spectroscopy (XPS) measurement was used to evaluate the chemical state of the ceria slurry in different recycling polishing time. Then, elastic moduli via atomic force microscope (AFM) force curves measurement of the abrasive ceria particles were measured and analyzed. And the change of shear viscosity of the slurry was monitored. In addition, the relative removal mechanism of fused silica using ceria slurry recycling was discussed.