| 摘要 |
PURPOSE:To obtain a SRAM and its test method which can detect existence of a minute leak current. CONSTITUTION:A semiconductor switch 34 which can be turned off at the time of a test is inserted between a power supply line Vdd and TFT 16, 18 of a memory cell 10. Data is written turning on the switch 34, after the switch 34 is turned off and a fixed time elapses, further, the switch 34 is turned on. After that, data is read out, a memory cell 10 in which written data is reversed is discriminated as a defect. It is performed for '1' and '0' of written data respectively. Also, leaving the switch 34 an off state, after data is written and a fixed time elapses, data is read out, a memory cell in which read-out of data cannot be performed can also be discriminated as a defect. Especially, when it is utilized for a product of an initial stage, a large merit is obtained. |
