Abstract
In order to reveal a chemical mechanical polishing (CMP) mechanism of a sapphire substrate by a colloidal silica abrasive grain, we investigated a polishing process of an α-Al_2O_3(0001) surface by a SiO_2 cluster under water environment by a first-principles calculation. The results show that the mechanical pressing by the SiO_2 cluster and the chemical reaction with a H_2O molecule introduce the break of the Al-O bond of the α-Al_2O_3(0001) surface. In addition, after the chemical reaction with H_2O, an Al(OH)_3 molecule is generated and desorbs from the α-Al_2O_3 surface in the CMP process.
