Patent attributes
A method of manufacturing a NAND flash memory device, including the steps of providing a semiconductor substrate in which a cell region and a select transistor region are defined; simultaneously forming a plurality of cell gates on the semiconductor substrate of the cell region and forming selection gates on the semiconductor substrate of the select transistor region; forming an oxide film on the entire structure and then forming a nitride film; etching the nitride film so that the nitride film remains only between the selection gates and adjacent edge cell gates; and, blanket etching the oxide film to form spacers on sidewalls of the selection gates. Accordingly, uniform threshold voltage distributions can be secured, and process margins for a spacer etch target can be secured when etching the spacers. Furthermore, the nitride film partially remains between the edge cell gates and the selection gates even after the gate spacers are etched. It is therefore possible to prohibit the infiltration of moisture or hydrogen ion, which may occur in a subsequent process.
