| 摘要 |
PURPOSE: A method for manufacturing a flash memory device is provided to achieve the pattering process in which the first polysilicon layer is used as a mask twice, and to form an LDD structure using twice ion-implantation processing in formation of drain junction region. CONSTITUTION: A tunnel oxide layer(2) and the first polysilicon layer are sequentially formed on a substrate(1) and firstly patterned. Channel ions are implanted into the exposed substrate. The first polysilicon layer and the tunnel oxide layer are secondly patterned to form a floating gate. An LDD region(4A) is formed between the floating gates. A dielectric film(5) and the second polysilicon layer are sequentially formed on the resultant structure. By patterning the second polysilicon layer and the dielectric film, a gate electrode(20) with a control gate(6A) is formed. The first interlayer dielectric(7) is formed by oxidizing the surface of the control gate. A source/drain region(4B) is then formed.
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