| 摘要 |
PROBLEM TO BE SOLVED: To increase effectively the capacities of floating gates or the capacity of a memory cell capacitor, by a method wherein a dielectric film, which has openings to reach an element isolation structure, and is formed in such a way as to cover the surface of a charge storage film comprising the inner surface of these openings, and a conductive film formed on the dielectric film, are provided on a substrate. SOLUTION: Approximately cylindrical openings 21 formed in a photoresist 6 are formed between open parts 7 formed in the photoresist 6 and an opening 8 formed in the photoresist 6 and thereafter, a polycrystalline silicon film 5 is selectively removed by a dry etching using the photoresist 6 as a mask. In this case, an etching is performed in the openings 8 and 21 until a lower field oxide film 2 is exposed and with roughly cylindrical openings 22 formed, recesses 20 are formed in the open parts 7. Then, after a dielectric film constituted of an ONO film is formed on the entire surface, a polycrystalline silicon film is formed on the dielectric film by a CVD method and composite gate electrodes are formed by patterning. |
