| 摘要 |
A method for manufacturing a flash memory device is provided to improve dielectric properties by using high-permittivity material as a dielectric film and to enhance sputter yield by changing the profile of a first polysilicon layer. A tunnel oxide layer(12), a first polysilicon layer(13), a nitride layer and a hard mask layer are sequentially formed on a substrate(11). A trench is formed by etching the hard mask layer, the nitride layer, the first polysilicon layer, the tunnel oxide layer and the substrate. An isolation layer(15) is formed by filling an oxide layer in the trench, polishing and removing the hard mask layer. A desired thickness of the isolation layer is etched. The nitride layer and the first polysilicon layer are simultaneously etched, thereby forming a trapezoid profile. After the remaining nitride layer are eliminated, a dielectric film(16) is formed. A second polysilicon layer(17) and a gate conductive layer(18) are sequentially formed on the dielectric film.
|
