| 摘要 |
PROBLEM TO BE SOLVED: To prevent charge through in the neighborhood of the upper end of a floating gate. SOLUTION: An element separation structure 13 is formed on a semiconductor substrate 12. An element separation gate oxide film is deposited, a floating gate film is deposited, a spacer oxide film is deposited, and an etching resistance mask pattern 20 is formed on the spacer oxide film. Isotropic etching is performed where the etching resistance mask pattern is used as a mask so as to form a spacer oxide film pattern 18, by removing the spacer oxide film of a region being larger than a region which is from the end edge 20c of the etching resistance mask pattern to the lower surface 20b of the etching resistance mask pattern, and is exposed from the etching resistance mask pattern. Aisotropic etching is performed, where the etching resistance mask pattern is used as the mask, so as to remove the floating gate film along the contour of the etching resistance mask pattern, and to form the floating gate 16 having an upper end surface 16e, which makes an obtuse angle relative to an exposure end surface 16c on an upper end 16d. COPYRIGHT: (C)2007,JPO&INPIT
|
