| 摘要 |
PROBLEM TO BE SOLVED: To provide a production method for semiconductor memory device for surely preventing gate electrode short-circuiting. SOLUTION: After a first floating gate electrode material film 4a is formed on a semiconductor wafer 1 through a first gate insulating film 3, an element isolation groove 8 is worked, an element isolation insulating film 10 is embedded in this element isolation groove 8 while being protruded from the surface position of the first floating gate electrode material film 4a, and a second floating gate material film 4b is deposited thereon. After the oxide film of a mask 11 is formed on this second floating gate electrode material film 4b, the second floating gate electrode film 4b is separated by a slit 13 on the element isolation insulating film 10 through etching with this mask 11 as a mask. Afterwards, the residue of the gate electrode material film 4b inside that slit 13 is removed by etching and next treated by washing and afterwards, the mask 11 is removed by etching.
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