Dynamic read disturb management algorithm for flash-based memory
AssigneeMicron Technology, Inc.
InventorsHua Tan, Zhen Shu, Nicola Colella
Life of this patent
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Abstract
A memory device comprises a memory array and a memory controller operatively coupled to the memory array. The memory controller includes a processor configured to initiate read operations to the memory array; compare the number of read operations to a predetermined threshold number of read operations; initiate scanning memory pages of a block of memory cells for errors in response to reaching the threshold number of read operations for the block; and iteratively change the threshold number to a new threshold number, perform the new threshold number of read operations on the block of memory cells, and error scan memory pages associated with the last read operation of the new threshold number of read operations.
Claims20
A memory device comprising:
- a memory array including memory cells;
- a memory controller operatively coupled to the memory array and including a processor, the processor configured to:
- initiate read operations to the memory array;
- compare the number of read operations performed on a block of memory cells of the memory array, to a predetermined threshold number of read operations;
- scan first, second and third memory pages of the block of memory cells for errors in response to reaching the threshold number of read operations for the block and not scanning when the threshold number of read operations is not reached, wherein the first memory page and the second memory page are attached to different neighboring access lines of a first access line used in a last read operation of the threshold number of read operations, the third memory page is attached to an access line experiencing more errors than the first and neighboring access lines, and wherein the first, second, and third memory pages are less than a number of memory pages tracked for the read operations;
- and
- iteratively change the threshold number to a new threshold number when the threshold number is reached regardless of whether errors are found by the scan, perform the new threshold number of read operations on the block of memory cells, and error scan first, second and third memory pages associated with the last read operation of the new threshold number of read operations.
A method of operating a memory device, the method comprising:
- selecting a threshold number of read operations to be performed on a block of memory cells of the memory device, wherein the block of memory cells includes multiple pages of memory cells;
- scanning first, second and third pages of the multiple pages for errors in response to reaching the threshold number of read operations and not scanning when the threshold number of read operations is not reached, wherein the first page and the second page are attached to different neighboring access lines of a first access line used in a last read operation of the threshold number of read operations, the third memory page is attached to an access line having more errors relative to the first and neighboring access lines, and wherein the first, second, and third memory pages are less than a number of memory pages tracked for the read operations;
- and
- iteratively changing the threshold number to a new threshold number when the threshold number is reached regardless of whether errors are found by the scanning, performing the new threshold number of read operations on the block of memory cells, and error scanning first, second and third pages associated with the last read operation of the new threshold number of read operations.
A non-transitory computer readable medium including instructions that, when performed by processing circuitry of a memory controller, cause the memory controller to perform acts comprising:
- selecting a threshold number of read operations to be performed on a block of memory cells of a memory array operatively coupled to the memory controller, wherein the block of memory cells includes multiple pages of memory cells;
- scanning first, second and third pages of the multiple pages for errors in response to reaching the threshold number of read operations and not scanning when the threshold number of read operations is not reached, wherein the first page and the second page are attached to different neighboring access lines of a first access line used in a last read operation of the threshold number of read operations, the third memory page is attached to an access line having more errors relative to the first and neighboring access lines, and wherein the first second and third memory pages are less than a number of memory pages tracked for the read operations;
- and
- iteratively changing the threshold number to a new threshold number when the threshold number is reached regardless of whether errors are found by the scanning, performing the new threshold number of read operations on the block of memory cells, and error scanning first, second and third pages associated with the last read operation of the new threshold number of read operations.
Dependencies are inferred from the claim text.