| abstract |
A silicon nitride film is first formed on a semiconductor substrate and serves as a polishing stopper film. Then, the silicon nitride film and the semiconductor substrate are etched in a predetermined region to form an isolating trench which partitions an active region. Next, a silicon dioxide film is deposited on the semiconductor substrate so that the isolating trench is filled with the silicon dioxide film. Next, first-stage chemical mechanical polishing (CMP) is performed with a SiO 2 -contained slurry which can efficiently polish the surface of the silicon dioxide film regardless of level difference. Finally, second-stage CMP is performed with a CeO 2 -contained slurry ensuring a large polishing selectivity ratio of the silicon dioxide with regard to silicon nitride films. |