Patent ID: 7968421
Filing Date: 2011-06-28
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device, comprising the steps of: forming hard mask patterns on the silicon substrate such that isolation areas are exposed; etching the exposed isolation areas of the silicon substrate to define trenches; forming an etch barrier layer comprising a nitride layer on sidewalls of the trenches; isotropically etching bottom portions of the trenches using the etch barrier layer and the hard mask patterns as an etch mask to form the spherical portions; defining bulb-type trenches having spherical portions in a silicon substrate; conducting an oxidation process to form oxide layers in surfaces of the spherical portions of the bulb-type trenches; forming an insulation layer on the silicon substrate including surfaces of the bulb-type trenches having the oxide layers formed therein; and etching the insulation layer to define isolation trenches, wherein the insulation layer is etched such that a portion of the insulation layer remains in the spherical portions of the bulb-type trenches, and wherein SOI structures having the oxide layers interposed between portions of the silicon substrate are formed.