| 摘要 |
PURPOSE:To isolate a digit line to which a defective cell is connected electrically completely from other lines when the defective cell is formed by providing an isolating means which can isolate the digit line completely from the other line on each digit line within a regular memory cell array. CONSTITUTION:Digit lines DL1-DL4 are connected to sense amplifiers SA1 and SA2 through fuses Fu1-Fu4 and also connected to a precharge-level line PL through transistors Q1, Q3, Q4 and Q6 and fuses Fu5 and Fu6. When an electric test is conducted in the wafer state and a defect is found in a memory cell MS1, the digit line to which the cell is connected is not selected, and the fuses Fu1, Fu2 and Fu5 are cut. In this way, the digit lines DL1 and DL2 are isolated from the other lines. Therefore, even if the digit lines and a word line are shorted, the effect is not received. Thus the chip can be saved as a good product. |
