Method of fabricating flash memory device

Abstract

A method of fabricating a non-volatile memory device forming a first polysilicon film over a semiconductor substrate; forming a mitigation film over the first polysilicon film; forming a mask film over the mitigation film; etching the mask film, the mitigation film, and the first polysilicon film to form a first trench that defines first and second floating gates; forming an interlayer film over the mask film, the interlayer film filling the first trench to form a vertical structure; anisotropically etching the vertical structure of the interlayer film to form second and third trenches, the second trench being provided between the first floating gate and the etched vertical structure, the third trench being provided between the second floating gate the and etched vertical structure; forming a dielectric film over the first and second floating gate and the vertical structure, the dielectric film coating sidewalls of the second and third trenches; and forming a control gate layer over the dielectric film, the control gate layer filling the first and second trenches.