Write Operations with Full Sequence Programming for Defect Management in Nonvolatile Memory

摘要

Data that is stored in a higher error rate format in a nonvolatile memory is backed up in a lower error rate format. Data to be stored may be transferred once to on-chip data latches where it is maintained while it is programmed in both the high error rate format and the low error rate format without being resent to the nonvolatile memory. High error rate format may be MLC format and programming in the high error rate format may program both lower page and upper page data together in a full sequence programming scheme that is suitable for handling high data volume.

主权项

1. A method of operating a nonvolatile memory array comprising:
receiving a first portion of data to be stored in the nonvolatile memory array; buffering the first portion of data in on-chip data latches; writing the first portion of data from the on-chip data latches to the nonvolatile memory array in Single Level Cell (SLC) format; subsequently receiving a second portion of data to be stored in the nonvolatile memory array; buffering the second portion of data in the on-chip data latches with the first portion of data; subsequently, writing the first and second portions of data together in Multi Level Cell (MLC) format in a word line of an MLC block as lower page and upper page data respectively; subsequently, receiving the second portion of data at least partially in parallel with the storing the first and second portions together in MLC format; subsequently storing the second portion of data in SLC format; subsequently comparing the second portion in MLC format with the second portion in SLC format to determine if the second portion in MLC format meets a standard; and discarding the first and second portions in SLC format only if the second portion in MLC format meets the standard.