Characteristics of Slurry Recycling in Chemical Mechanical Polishing (CMP) of Fused Silica (FS)

Fused silica (FS) has attracted much attention and is widely applied in astronomical telescopes, laser systems, semicouductor industry, and optical communication. Based on the ultra-smooth surface polishing of fused silica using silica slurry, the variations of polishing performance of fused silica in the recycling polishing were studied. Meanwhile, the variations of slurry characteristics in chemical mechanical polishing (CMP) of fused silica were investigated. The variations of the average size and the morphology of the abrasive silica particles were observed. And the change of pH value and the conductivity of the slurry were monitored. The thermal gravimetric analysis (TGA) was used to evaluate the chemical change of the abrasive silica particles. Then, elastic moduli via atomic force microscope (AFM) force curves measurement of the abrasive particles were measured and analyzed. In addition, the relative removal mechanism of fused silica was discussed.