Patent ID: 7919370
Filing Date: 2011-04-05
Classification: H01L

Abstract:
1. A method of manufacturing a flash memory device, comprising: forming a tunnel oxide film on a semiconductor substrate; forming an auxiliary floating polysilicon layer on the tunnel oxide film; forming an ONO film on the auxiliary floating polysilicon layer; forming a control polysilicon layer on the ONO film; forming a hard mask layer comprising an oxide, a nitride, or both on the control polysilicon laver; patterning the hard mask layer to form a hard mask layer pattern on the control polysilicon layer; forming a control gate by patterning the control polysilicon layer using the hard mask layer pattern as a etch mask; forming an auxiliary ONO pattern by patterning the ONO film; forming a floating gate by patterning the auxiliary floating polysilicon layer using an etchant with a high etching selectivity to polysilicon, wherein the auxiliary ONO pattern is provided with a portion that projects out farther than a side of the control gate; and removing the hard mask layer pattern, wherein during removal of the hard mask layer pattern, the portion of the auxiliary ONO pattern that projects out farther than a side of the control gate is removed to form an ONO pattern.