| 摘要 |
PURPOSE:To attain the enhancement of capacity of EPROM or E<2>PROM or the improvement in cell characteristics by separating an oxide film by a minute width beyond the limit of exposure technique by volume expansion at a time when an oxidizable film is oxidized to be converted into an oxide film. CONSTITUTION:After a polysilicon film 16 is separated by the separation width of 0.8mum which is the limit of exposure technique during aprocess (a), by thermal oxidation effected during a process (b), the polysilicon film 16 is converted into a polysilicon oxide film 18 and the volume expansion is done thereby making the separation width 0.4mum. As a result, the final floating gate 22 can be separated by minute separation width beyond the limit of exposure technique by etching a silicon nitride film 15 by using a reactive ion gas and the polysilicon oxide film 18 as a mask, and further etching a polysilicon film 14 by using the silicon nitride film 15 as a mask after removing the polysilicon oxide film 18. |
