| 摘要 |
A method for manufacturing a flash memory device is provided to improve the coupling ratio between a floating gate and a control gate by filling a polysilicon layer in voids. A trench is formed in a substrate(10) having a screen oxide layer and a pad nitride layer. An isolation layer(15) is formed in the trench. By removing the pad nitride layer and the screen oxide layer, an isolation nipple protruded on the surface of the substrate is exposed. A first polysilicon layer(17) is deposited on the resultant structure. By etch-back of the resultant structure, voids in generated in the first polysilicon layer are exposed. A second polysilicon layer is deposited to fill the voids, thereby removing the voids.
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