Patent ID: 6235589
Filing Date: 2001-05-22
Classification: H01L

Abstract:
A method of fabricating a semiconductor device comprising the steps of:forming a gate oxide film on a semiconductor substrate;forming a first polycrystalline silicon film on said gate oxide film;forming a first insulating film on said first polycrystalline silicon film and then patterning said first insulating film;removing said first polycrystalline silicon film and said gate oxide film with said patterned first insulating film used as a mask, thereby exposing a surface of said semiconductor substrate;removing said exposed area of said semiconductor substrate to a desired depth, thereby forming a trench in said semiconductor substrate;forming an oxide film on exposed surfaces of said semiconductor substrate and said first polycrystalline silicon film;forming a second insulating film on an entire surface, thereby burying said trench;planarizing said second insulating film, thereby exposing a surface of said first insulating film;removing said first insulating film;removing said second insulating film and said oxide film, thereby exposing an upper portion of said first polycrystalline silicon film;forming a second polycrystalline silicon film on an entire surface;removing said second polycrystalline silicon film, thereby forming sidewall spacers on sides of said first polycrystalline silicon film; andforming an ONO film on an entire surface.