Patent ID: 7736990

Claim:
A method for manufacturing a semiconductor device, comprising: forming a first insulating film to be used as a mask for forming a trench region directly above a semiconductor substrate; forming the trench region on the semiconductor substrate using the mask; forming a second insulating film directly above the semiconductor substrate which includes the trench region and the first insulating film so that the second insulating film has a recess above the trench region and a protrusion above the first insulating film; removing the protrusion down to the bottom of the recess as a first removal step; and removing the first insulating film and the second insulating film in accordance with a chemical mechanical polishing method so that the step formed of the recess and protrusion is reduced to 20 nm or less as a second removal step, wherein the first insulating film and the second insulating film are made of insulating films having no difference in the polishing rate under the same conditions for chemical mechanical polishing in the second removal step, in the second removal step, a slurry including 0.2 to 0.6% by weight of abrasive particles is used, and the first insulating film and the second insulating film are insulating films having the same composition and the second insulating film is a silicon oxide film formed by a high density plasma CVD method.