Patent ID: 7049236
Filing Date: 2006-05-23
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device, comprising: (a) sequentially forming a tunnel oxide film, a first polysilicon film and a pad nitride film on a semiconductor substrate; (b) etching portions of the pad nitride film, the first polysilicon film, the tunnel oxide film and the semiconductor substrate by means of a patterning process to form a trench within the semiconductor substrate; (c) depositing an oxide film on the entire structure including the trench and then planarizing the oxide film so that the pad nitride film is exposed; (d) etching the pad nitride film to form an oxide film protrusion; (e) depositing a second polysilicon film on the entire structure and then planarizing the second polysilicon film so that the oxide film protrusion is exposed, thereby forming a floating gate having the second polysilicon film formed on the first polysilicon film; and (f) etching a part of the exposed oxide film protrusion to improve a coupling ratio, and then forming a dielectric film and a control gate.