Method of making complete dielectric isolation structure in semiconductor integrated circuit

摘要

For controlling unwanted production of crystal defects from corners (6, 7) of isolated regions in a complete dielectric isolation structure, after at least one trench (5) or groove is provided through a mask of an insulating film (4) in a semiconductor substrate (3) adhered to an insulating film (2) of a base substrate (1), the mask (4) is side-etched and the insulating film (2) of the base substrate (1) is selectively etched at the same time to expose corners (6, 7) of the semiconductor substrate (3). The exposed corners (6, 7) of the semiconductor substrate (3) is then subjected to isotropic etching to remove a pointed portion therefrom. Thereafter, side surfaces of the semiconductor substrate (3) exposed within the trench (5) is oxidized to provide an insulting film (8) for dielectric isolation which has rounded corners.