METHOD OF MANUFACTURING A NON-VOLATILE MEMORY DEVICE

摘要

A method for manufacturing a nonvolatile memory device is provided to prevent a pitting of a first poly silicon layer due to an over etch of a spacer and degradation of a gate oxide layer by using a floating gate made of first and second poly silicon layer patterns. A mask pattern is formed on a substrate(100) where a first poly silicon layer, an etch stop layer, and a silicon nitride layer are sequentially formed. The silicon nitride layer exposed to the mask pattern is etched to form a first silicon nitride layer pattern having a first width. A second silicon nitride layer pattern is formed by oxidizing a side of the first silicon nitride layer pattern. A silicon oxynitride layer is formed on a side of the second silicon nitride pattern. The silicon oxynitride layer exposed to the mask pattern is etched to form a silicon oxynitride layer pattern(116) formed on the second silicon nitride pattern. The etch stop layer, the first poly silicon layer, and the substrate exposed to the mask pattern are sequentially etched to form etch stop layer patterns(126), first poly silicon layer patterns(124), and a trench(118) on the substrate. A preliminary isolation layer is formed as the trench is buried. An upper surface of the preliminary isolation layer is the same height as upper surfaces of the second silicon nitride pattern and the silicon oxynitride layer pattern. The second silicon nitride layer pattern and the exposed etch stop layer pattern are removed to form an opening unit(130) exposing the surface of the first poly silicon layer pattern. A second poly silicon layer pattern(134) is formed on the opening unit to form a floating gate(140) where the first poly silicon layer pattern and a second poly silicon layer pattern are stacked.