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US 2010/0167515 A1Published application
Method for fabricating flash memory device
AssigneeDongbu HiTek Co., Ltd.
InventorKi-Jun Yun
Life of this patent
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Abstract
A method of forming a flash memory device includes forming a plurality of memory gates over a semiconductor substrate, forming an oxide film over the uppermost surface and sidewalls of the memory gates and then forming a plurality of selective gates on sidewalls of each of the memory gates.
Claims20
A method comprising:
- forming an insulating film having a multilayered structure over a semiconductor substrate;
- forming a memory gate over the insulating film;
- forming a gate oxide film over the uppermost surface and sidewalls of the memory gate;
- forming a first polysilicon layer over an entire surface of the semiconductor substrate including the memory gate and the gate oxide film;
- forming a second polysilicon layer over an entire surface of the first polysilicon layer;
- performing a first etching process on the first polysilicon and the second polysilicon;
- and then
- forming selective gates by performing a second etching process on the first polysilicon layer.
5 more elements
A method comprising:
- forming a plurality of memory gates spaced apart over a semiconductor substrate by forming a first polysilicon layer over the semiconductor substrate and then performing a first etching process on the first polysilicon film;
- forming a gate oxide film over the uppermost surface and sidewalls of the memory gates by performing an oxidation process;
- forming a second polysilicon layer over the semiconductor substrate, the memory gates and the gate oxide film;
- forming a third polysilicon layer over the uppermost surface of the second polysilicon layer;
- performing a second etching process on the first polysilicon and the second polysilicon;
- and then
- forming a plurality of selective gates in the spaces between neighboring memory gates by performing a third etching process on the second polysilicon layer.
4 more elements
A method comprising:
- forming a first insulating film over a semiconductor substrate;
- forming a plurality of memory gates over the first insulating film;
- forming a second insulating film over the uppermost surface and sidewalls of respective one of the memory gates by performing an oxidation process;
- forming a first polysilicon layer over the first insulating film, the memory gates and the second insulating film such that the first polysilicon layer has a plurality of grooves formed in an uppermost surface thereof;
- forming a second polysilicon layer over the uppermost surface of the first polysilicon layer to fill the grooves in the first polysilicon layer;
- simultaneously removing the second polysilicon layer and planarizing the uppermost surface of the first polysilicon;
- and then
- forming a plurality of selective gates on sidewalls of each of the memory gates by etching the second polysilicon layer.
5 more elements
Dependencies are inferred from the claim text.