| 摘要 |
A method of manufacturing a NAND type flash memory device is provided to prevent profile distortion of a floating gate by reducing a step between an isolation layer and an active region. A tunnel oxide layer(12), a first polysilicon layer(13), a buffer oxide layer, and a pad nitride layer are sequentially formed on a semiconductor substrate(11). A trench is formed by etching partially the pad nitride layer, the buffer oxide layer, the first polysilicon layer, and the tunnel oxide layer. An insulating layer(16) is formed to bury the trench. The insulating layer is polished by performing a first polishing process. The pad nitride layer is removed by performing a second polishing process. An isolation layer is formed by removing the buffer oxide layer. A second polysilicon layer is formed on the entire structure and a floating gate is formed by patterning the second polysilicon layer. A dielectric layer and a conductive layer are formed thereon. A control gate is formed by patterning the conductive layer and the dielectric layer.
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