A method of manufacturing a nonvolatile memory device comprises forming a gate insulating layer and a first conductive layer over a semiconductor substrate that defines a first area in which selection lines will be formed and a second area in which word lines will be formed, performing an etch process to lower a height of the first conductive layer in the first area, forming a dielectric layer and a second conductive layer over the first conductive layer with a height that is different from the height of the first conductive layer, and performing a gate patterning process to form the selection lines and the word lines.