Polishing composition and method for polishing substrate using the composition

A polishing composition comprising an abrasive, a base compound, a silicon oxide removal rate controller, and an oxidizer, wherein

• the abrasive is a silica abrasive with a primary particle size ranging from about 60 nm to about 70 nm, a secondary particle size ranging from about 110 nm to about 130 nm, its surface is unmodified, and it is present in a concentration of from about 0.1 wt % to about 2.5 wt %;
• the base compound is potassium hydroxide and is present at a concentration of from about 0.2 wt % to about 0.5 wt %;
• the silicon oxide removal rate controller is selected from the group consisting of N-cyclohexyl-3-aminopropanesulfonic acid (CAPS), 4-(cyclohexylamino)butane-1-sulfonic acid (CABS), 3-(cyclohexylamino)-2-hydroxy-1-propanesulfonic acid (CAPSO), and N-cyclohexyl-2-aminoethanesulfonic acid (CHES), and is present at a concentration of from about 0.8 wt % to about 1.2 wt %;
• and
• the oxidizer is hydrogen peroxide and is present at a concentration of from about 0.8% wt to about 1.2% wt,
• wherein the pH of the polishing composition is from about 9.5 to about 10.5.