Patent ID: 7754611

Claim:
A chemical mechanical polishing method, comprising: forming a film on a wafer having at least one trench structure thereon, the trench structure including first and second dielectric liner layers sequentially disposed along sidewalls of the trench and each having portions extending away from the trench substantially parallel to an upper surface of the wafer, and the first dielectric liner layer disposed between the second dielectric liner layer and the trench sidewalls and the upper surface of the wafer; polishing the surface of the film by providing a first polishing composition to provide a first polished surface of the film and of the extending portion of the second dielectric liner layer overlying the upper surface of the wafer; rinsing the first polished surface with a rinse composition to dilute the first polishing composition; and polishing the first polished surface by providing a second polishing composition to provide a second polished surface of the film and of the extending portion of the first dielectric liner layer overlying the upper surface of the wafer, the extending portion of the second dielectric liner layer overlying the upper surface of the wafer being substantially removed, wherein the first polishing composition and the second polishing composition have the same slurry composition.