Dynamic Memory Recovery at the Sub-Block Level

A non-volatile flash memory has bit lines spanning multiple blocks grouped into columns, where each block is connected along multiple regular columns and one or more redundancy columns. When there is a local column defect, so that the defect is not at the level of the whole block or global column, the portions of a column at an individual block can be remapped to a portion of the same block along a redundant column. Sections of multiple columns from different blocks can be remapped to the same redundancy column. Then a memory block includes a number of independently accessible sub-blocks, the process can also be implemented at the sub-block level. A dynamic, system level implementation is presented.