Patent ID: 6844231
Filing Date: 2005-01-18
Classification: H01L

Abstract:
1. A method of manufacturing a flash memory cell comprising: forming a pad oxide film and a pad nitride film on a semiconductor substrate; forming a trench in the semiconductor substrate; removing the sacrifice oxide film and forming a wall oxide film on an internal surface of the trench; forming a trench insulating film on the entire structure and then implementing a first chemical mechanical polishing (CMP) process to isolate the trench insulating film; removing the pad nitride film, by which a given portion of the trench insulating film forms a protrusion; performing an etch process to etch the protrusion of the trench insulating film a given width; forming a first polysilicon layer on the entire structure and then implementing a second CMP process to form a floating gate; and forming a dielectric film and a second polysilicon layer on the entire structure and then implementing an etch process to form a control gate.