| 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 preventing the deterioration of the characteristics of a gate oxide layer and a gate electrode. SOLUTION: The method of manufacturing the flash memory element includes a step of forming the gate oxide layer and a first polysilicon layer on a semiconductor substrate; a step of forming a buffer oxide layer on the first polysilicon layer; and a step of forming an element isolating trench by successively etching a nitride layer, the buffer oxide layer, first polysilicon layer, gate oxide layer, and semiconductor substrate after the nitride layer is formed on the buffer oxide layer. The method also includes a step of forming a field oxide film in the trench by polishing an element isolating oxide layer and the nitride layer by fixed thicknesses after the element isolating oxide layer is vapor-deposited on the whole structure including the trench, a step of removing the nitride layer by performing a nitride removing process, and a step of removing the buffer oxide layer by performing an oxide removing process. In addition, the method also includes a step of forming a second polysilicon layer on the first polysilicon layer containing a field oxide film. COPYRIGHT: (C)2005,JPO&NCIPI
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