| 摘要 |
PURPOSE:To improve the production yield of semiconductor memory devices by replacing a faulty area of a redundant memory cell to be replaced with a faulty memory cell with another redundant memory cell. CONSTITUTION:Selection circuits 14a-14j for relief of faults serve as fuse elememts put between redundant selection circuits 8a-8j and selection lines 6a-6j. The faults are detected with normal memory cells 1a-1n and 2a-2n, and these cells are replaced with redundant memory cells 3a-3n and 4a-4n respectively. However, these replaced redundant cells may sometimes have faults. In such a case, the fuse elements 14a-14j corresponding to the faulty redundant memory cells are cut off by a proper means. Then the corresponding memory cell is put under a non-selection state. A redundant control circuit is programmed so as to select a new redundant memory cell in place of the memory cell put in a non-selection state. In such a way, the generation of faults can be reduced. This improves greatly the production yield of semiconductor memory devices. |
