METHOD OF RECYCLING A SUBSTRATE

摘要

A method for recycling a substrate is provided to planarize an upper surface of the substrate by using a fumed silica and a colloidal silica. A first chemical mechanical polishing process is performed to remove a stepped part of an edge region of a substrate by using a slurry including a fumed silica(S100). A second chemical mechanical polishing process is performed to improve roughness of a surface of the substrate by using a slurry including a colloidal silica(S110). The slurry composition used in the first chemical mechanical polishing process includes fumed silica polishing particles of 5 to 20 weight percent, KOH of 1 to 5 weight percent, ammonium salt of 0.01 to 1.0 weight percent, and water of the remaining weight percent. The KOH is used as an additive for controlling pH. The ammonium salt is used as an additive for controlling a particle size.