Patent ID: 6436789
Filing Date: 2002-08-20
Classification: H01L

Abstract:
A method for forming a device separation region, comprising:forming a plurality of trenches in a semiconductor substrate, said plurality of trenches including first trenches each having a width which is greater than a given width and second trenches each having a width which is less than the given width; forming a first insulating film over said plurality of trenches and said semiconductor substrate; forming a resist layer on said first insulating film; patterning said resist layer such that remaining portions of said resist layer extend over said first trenches and such that removed portions of said resist layer extend completely over said second trenches; forming second device separating regions by etching said first insulating film using said remaining portions of said resist layer as a mask to expose said second trenches, wherein said second device separation regions are respectively defined by said second trenches containing said first insulating film; removing said remaining portions of said resist layer to expose portions of said first insulating film protruding above said first trenches; forming a second insulating film over the second trenches and the exposed portions of the first insulating film; and forming first device separation regions by chemical mechanical polishing said second insulating film and the exposed portions of said first insulating film protruding above said first trenches, wherein said first device separation regions are respectively defined by said first trenches containing said first insulating film; wherein said given width is 80 percent of a thickness of said first insulating film.