| 摘要 |
A testing pad is connected to an EEPROM through a wiring layer of a security circuit and a test circuit, while a testing pad is connected to the EEPROM through a wiring different from the wiring layer and the test circuit. A polysilicon pattern is connected to the wiring layer, and an n-type diffusion region is connected to the wiring. A tunnel insulation film having a thickness of about 100 ANGSTROM is formed between the polysilicon pattern and the n-type diffusion region. After a test for the function and stored information of the EEPROM is completed, a voltage, which is not lower than a predetermined voltage applied during the test, is applied between the testing pads to break the tunnel insulation film, thereby making the polysilicon pattern and n-type diffusion region conductive.
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