Systems and methods for lower page writes

摘要

In a Multi Level Cell (MLC) memory array block in which lower pages are written first, before any upper pages, the lower page data is subject to an exclusive OR (XOR) operation so that if any lower page becomes uncorrectable by ECC (UECC) then the page can be recovered using XOR. Lower pages in such blocks may be written in nonsequential order.

主权项

1. A method of operating a Multi Level Cell (MLC) nonvolatile three dimensional memory that is monolithically formed in one or more physical levels of arrays of memory cells having an active area above a silicon substrate, comprising:
programming a plurality of word lines of a block of the MLC nonvolatile three dimensional memory with lower page data, leaving unwritten upper page capacity along the plurality of word lines; performing an Exclusive OR (XOR) operation on the lower page data of the plurality of word lines of the block; subsequently, maintaining results of the XOR operation for a period of time after the lower page data is programmed; and during the period of time when results of the XOR operation are maintained, writing upper page data along the plurality of word lines of the block.