METHOD OF MANUFACTURING A FLASH MEMORY DEVICE

摘要

A method for manufacturing a flash memory device is provided to prevent occurrence of seams within a deposited polysilicon layer by changing a negative slope of a depositing target region into a positive slope. A trench insulating layer(39) is formed on a field region of a semiconductor substrate(31). A tunnel oxide layer(40) is formed on the entire surface of the semiconductor substrate. A first polysilicon layer(41) is formed on the tunnel oxide layer. An upper part of the trench insulating layer and a part of the first polysilicon layer of a protrusion region are oxidized. The oxidized part of the first polysilicon layer is removed. A second polysilicon layer is formed on the entire surface of the semiconductor substrate. A floating gate including the first and second polysilicon layers is formed on an active region of the semiconductor substrate. An ONO(Oxide Nitride Oxide) dielectric layer is formed on the floating gate. A control gate is formed on the dielectric layer.