摘要 |
A sidewall core that is slimmed is formed in a memory cell array area by patterning a polysilicon layer formed over a silicon nitride layer. A silicon oxide layer that at least covers side surfaces of the sidewall core and the polysilicon layer are sequentially formed and an embedded hard mask is formed by etching back the polysilicon layer. Thereafter, the silicon nitride layer within the memory cell array area that does not overlap with the sidewall core or the embedded hard mask and the silicon nitride layer within a peripheral circuit area that overlaps with a positioning monitor mark are exposed by etching the silicon oxide layer, and then the silicon nitride layer that is to be etched is patterned. |