Method of performing copyback operation in nonvolatile memory device, and nonvolatile memory device and storage device performing the same

Abstract

In performing a copyback operation, a copyback command for target data that are programmed in a source area based on first voltage levels is received. A hard data read operation and a soft data read operation are performed on the target data based on the copyback command. Memory cells in the source area are classified into normal memory cells and weak memory cells, based on results of the hard data read operation and the soft data read operation. A first copyback program operation in which first data among the target data are stored in a destination area is performed, based on second voltage levels. The first data correspond to the normal memory cells. A second copyback program operation in which second data among the target data are stored in the destination area is performed, based on third voltage levels. The second data correspond to the weak memory cells.