US Patent 7948794 Nonvolatile memory device using variable resistive element

A nonvolatile memory device includes multiple memory blocks divided into multiple memory block groups. Each memory block group includes at least two memory blocks of the multiple memory blocks. The nonvolatile memory device also includes a main word line common to the memory blocks, and multiple sub-word lines corresponding to the memory blocks. Sub-word lines of the multiple sub-word lines located within the same memory block group are electrically connected to each other, and sub-word lines of the multiple sub-word lines located in different memory block are electrically isolated from each other.