Polishing composition and polishing method

摘要

To provide a polishing composition suitable for use to polish a silicon dioxide film, particularly for use to polish a silicon dioxide film formed on a silicon substrate or a polysilicon film, and a polishing method by means of such a polishing composition. The polishing composition of the present invention comprises a colloidal silica having a degree of association of more than 1, and an acid, and has a pH of from 1 to 4. The acid is preferably at least one member selected from the group consisting of a carboxylic acid and a sulfonic acid. This polishing composition preferably further contains an anionic surfactant. The anionic surfactant is preferably a sulfuric acid ester or a sulfonate.