Back to results
US 7,682,894 B2Granted
Flash memory and a method of manufacturing the same
AssigneeDongku Hitek Co., Ltd.
InventorSang-Woo Nam
Life of this patent
Estimating the term…
Abstract
The present invention provides a method of manufacturing a flash memory device. The method includes forming a gate oxide layer on a semiconductor substrate, forming a floating gate including protrusions and depressions on its surface by patterning polysilicon deposited on the gate oxide layer, depositing a dielectric layer on the floating gate and the gate oxide layer, and forming a control gate by patterning polysilicon deposited on the dielectric layer.
Claims14
A method of manufacturing a flash memory device, comprising:
- forming a gate oxide layer on a semiconductor substrate and a shallow trench isolation formed in the semiconductor substrate, wherein said gate oxide layer is formed to directly contact the uppermost surface of both the semiconductor substrate and the shallow trench isolation;
- depositing a first polysilicon layer on the gate oxide layer;
- performing a first exposure and development process for a first photoresist deposited on the first polysilicon layer;
- forming grooves in the first polysilicon layer by etching a surface of the first polysilicon layer by using the first photoresist as a mask;
- removing the first photoresist;
- filling the grooves in the first polysilicon layer using a third photoresist;
- performing an etch back for the third photoresist;
- performing a second exposure and development process for a second photoresist deposited on the first polysilicon layer;
- forming a floating gate including protrusions and depressions on the uppermost surface of the floating gate by patterning the first polysilicon layer and the gate oxide layer by using the second photoresist as a mask;
- depositing a dielectric layer on the floating gate and the gate oxide layer, wherein said dielectric layer is formed to directly contact the shallow trench isolation, the floating gate and sidewalls of the gate oxide layer;
- and
- forming a control gate by patterning a second polysilicon layer deposited on the dielectric layer.
9 more elements
A method of manufacturing a flash memory device, comprising:
- forming a gate oxide layer directly on an entire surface of a semiconductor substrate;
- depositing a first polysilicon layer directly on the gate oxide layer;
- forming a first photoresist directly on the first polysilicon layer and patterning the first photoresist using a first mask to forming a plurality of first photoresist patterns spaced apart by grooves 45 nm in width on the uppermost surface of the first polysilicon layer;
- removing the first photoresist patterns and performing a first cleaning of the uppermost surface of the first polysilicon layer;
- forming a second photoresist directly on the first polysilicon layer and in the grooves;
- exposing portions of the upper surface of the first polysilicon layer having no grooves using a dry ashing process;
- removing the second photoresist and performing a second cleaning of the uppermost surface of the first polysilicon layer;
- forming a third photoresist directly on the first polysilicon layer and in the grooves;
- forming a floating gate having protrusions and depressions on an uppermost surface thereof by etching the first polysilicon layer and the gate oxide layer using the third photoresist as a mask;
- and then
- forming a dielectric layer on the semiconductor substrate including the floating gate and the gate oxide layer, wherein said dielectric layer is formed to directly contact the floating gate and the gate oxide layer;
- and
- forming a control gate on the dielectric layer.
10 more elements
Dependencies are inferred from the claim text.