A memory device capable of rescuing defective characteristics that occur after packaging includes a memory cell array including a plurality of memory cells and an antifuse circuit unit including at least one antifuse. The antifuse circuit unit stores a defective cell address of the memory cell array in the at least one antifuse and reads the defective cell address to an external source. The antifuse circuit unit stores a defective characteristic code in the at least one antifuse, wherein the defective characteristic code is related to at least one of a timing parameter spec., a refresh spec., an input/output (I/O) trigger voltage spec., and a data training spec. of the memory device, and outputs the defective characteristic code to an external source.