Patent ID: 7682901

Claim:
A method for fabricating a nonvolatile memory device, the method comprising: forming a tunneling insulation layer and a conductive layer for a floating gate over a substrate; partially etching the conductive layer, the tunneling insulation layer, and the substrate to form a trench; forming an isolation layer filling a portion of the trench; forming spacers on both sidewalls of the conductive layer which is not covered by the isolation layer; recessing a portion of the exposed isolation layer using the spacers as an etch barrier layer to form a wing spacer; removing the spacers; performing a primary cleaning process on the resulting substrate, where the spacers are removed, using a mixed solution of sulphuric acid (H 2 SO 4 ) and hydrogen peroxide (H 2 O 2 ) and a mixed solution of ammonium hydroxide (NH 4 OH), H 2 O 2 , and H 2 O; and performing a secondary cleaning process on the resulting structure, where the primary cleaning process is completed, using a mixed solution of a hydrogen fluoride (HF) solution and a deionized water and a mixed solution of NH 4 OH, H 2 O 2 , and H 2 O.