| 摘要 |
PROBLEM TO BE SOLVED: To form an accurate desired gate electrode by suppressing an electron shading damage and reducing positive charging by a polysilicon electrode, in a manufacturing method for semiconductor memory and an etching method for gate electrode using a plasma dry etching method for flash memory or DRAM, etc., having a floating gate. SOLUTION: In a method for etching a gate electrode of a nonvolatile semiconductor memory, a first polysilicon layer on a thin oxidized film on a silicon substrate is etched to a specified thickness in a first etching step, and etching is continued under conditions where the plasma density is 1×1010 cm-3 or lower, the electron temperature is 3 eV or lower, and the selection ratio to oxidized film is 100 or more, in a second etching step until the thin oxidized film appears.
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