A method of manufacturing a nonvolatile memory device includes forming a tunnel dielectric layer, a charge storage layer, and a hard mask layer on a substrate in sequential order. Active portions are defined by forming trenches in the substrate. A tunnel dielectric pattern, a preliminary charge storage pattern, and a hard mask pattern are formed on each of the active portions in sequential order by sequentially patterning the hard mask layer, the charge storage layer, the tunnel dielectric layer, and the substrate. A capping pattern is formed covering an upper surface of the trenches such that a first void remains in a lower portion of the trenches, the capping pattern including etch particles formed by etching the hard mask pattern through a sputtering etch process.