Method of forming nonvolatile memory device

Abstract

Disclosed herein is a method of forming a nonvolatile memory device. The method comprises steps of forming a tunnel insulation pattern and a first floating gate pattern that are sequentially stacked on a semiconductor substrate, and then forming a trench comprising sidewalls aligned with the first floating gate pattern in the semiconductor substrate. Next, a device isolation layer is formed to fill in the trench, and an etch stop layer and a mold layer are sequentially formed on the device isolation layer and on the first floating gate pattern. The mold layer and the etch stop layer are successively patterned to form a groove exposing at least the first floating gate pattern, and a second floating gate pattern is formed to fill in the groove. This method can prevent bridges of floating gate layer that usually occur from regions not being fully etched due to high device integration.