Nonvolatile semiconductor memory device, such as an EEPROM or a flash memory, with reference cells

摘要

To set a threshold of a reference cell in short time in a semiconductor memory device using a variable threshold type nonvolatile memory cell as a reference current/voltage generating unit, a memory cell which keeps an initial state during an inspection process without performing write/erase operations is provided in an area of a memory cell storing data, and Vt setting of a reference cell is performed while the verification of the reference cell is performed on the basis of the memory cell which keeps the initial state during the inspection process.