POLISHING COMPOSITION AND POLISHING PROCESS

摘要

To provide a polishing composition which is suitable particularly for an application to polish a wafer containing tungsten, and a polishing process employing such a polishing composition. The polishing composition of the present invention comprises a colloidal silica and hydrogen peroxide. The pH of the polishing composition is from 1 to 4, and the concentration of iron ions in the polishing composition is at most 0.02 ppm. The polishing composition preferably further contains phosphoric acid or a phosphate.