| 摘要 |
PURPOSE: A method for manufacturing a flash memory device is to improve an electrical characteristic of the flash memory device by forming a well region using metal silicide. CONSTITUTION: An oxide film(12), a pad polysilicon layer(13), a metal silicide layer(14), the first undoped polysilicon layer(15), and a buffer oxide film(16) are subsequently formed on a substrate(11). A selected portion of the film and layers is etched using the first isolation oxide mask to form the first trench(17). An intermediate thermal oxide film(18) is formed on the entire surface of the substrate, and is carried out through a planarization procedure until the buffer oxide film is exposed, so that the first trench is buried by the intermediate thermal oxide film. The selected region of the buffer oxide film and the first undoped polysilicon layer are etched to form the second trench(19). The second undoped polysilicon layer(20) is formed on the entire surface of the substrate, and is carried out through the planarization procedure.
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