Abstract: Provided is a memory device including a nonvolatile memory for storing data and a password in a designated address, a password comparison circuit for comparing an externally input first password with a second password stored in the nonvolatile memory, a volatile memory for storing authentication information indicating that access right establishment is authenticated, if the two passwords are found to be equal by the comparison, and an access control circuit for permitting external access to the nonvolatile memory only when the authentication information is stored in the volatile memory.

Abstract: On a semiconductor wafer, there are formed chip areas for storing memory areas, scribe areas for cutting the semiconductor wafer, pads for supplying electric signals from the outside in order to write data into the memory areas, and lead wires for electrically connecting the pads with the memory areas. The pads are formed within the scribe areas. After data has been written into the memory areas through the pads, the semiconductor wafer is cut along the scribe areas, thereby obtaining semiconductor chips. At the time of this cutting, the pads or the lead wires are cut.