| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing flash memory element by which the reliability of a flash memory element can be improved by securing the stability of a process by improving the EFH differences induced among a cell region, a high-voltage transistor region, and a low-voltage transistor region by the projecting sections of the field oxide films of the regions. SOLUTION: The method of manufacturing the flash memory element includes a step of providing a semiconductor substrate on which the cell region, high-voltage transistor region, and low-voltage transistor region are defined; a step of forming high-EFH field oxide films respectively in the cell region and low-voltage transistor region of the semiconductor substrate, and a low-EFH field oxide film in the high-voltage transistor region of the semiconductor substrate based on the topological differences among the gate oxide films formed in the regions; and a step of making the EFHs of the field oxide films formed in the regions equal or similar to each other by etching the high-EFH field oxide films by fixed thicknesses in a step of recessing the field oxide films. COPYRIGHT: (C)2005,JPO&NCIPI
|
