Redundancy scheme for eliminating defects in a memory device

Abstract

A redundancy scheme for a memory device, as well as a method for developing a redundancy scheme, resulting in improved repairability for given space constraints. A memory device is formed with a plurality of data blocks having individual input/output paths. Each block comprises an array of memory cells arranged in addressable rows and columns along row lines and column lines. The array is configured in sub-blocks each comprising a plurality of the memory cells. The device includes row address circuitry for selecting a row of the memory cells, column address circuitry for selecting a column of the memory cells and address repair circuitry. The address repair circuitry is configurable to render a first portion of a first of the columns of cells responsive to the address of a portion of a second of the columns of cells. There is also provided a method for eliminating a defect in a memory device having a logical data block formed with addressable rows and columns of memory cells. A defect associated with a first column of cells is eliminated by programming a portion of a second column of cells to be responsive to the addresses of a portion of the cells in the first column.