Non-volatile memory and method with accelerated post-write read using combined verification of multiple pages
First Claim
1. A method of operating a memory system including an array of non-volatile cells formed along a plurality of bit lines and a plurality of word lines, the word lines each capable of storing one or more pages of data, the method comprising:
- writing multiple pages of data into the array;
subsequently reading a plurality of the written pages of data from the array;
forming a composite data structure of the plurality of read pages, wherein forming a composite data structure of the plurality of read pages includes performing an exclusive OR operation of the plurality of read pages on a bit line by bit line basis; and
performing an evaluation of at least a portion of the composite data structure to determine the presence of high error rate in the plurality of pages of data as written.
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Abstract
A post-write read operation, using a combined verification of multiple pages of data, is presented. In a simultaneous verification of multiple pages in a block, the controller evaluates a combined function of the multiple pages, instead of evaluating each page separately. In one exemplary embodiment, the combined function is formed by XORing the pages together. Such a combined verification of multiple pages based on the read data can significantly reduce the controller involvement, lowering the required bus and ECC bandwidth for a post-write read and hence allow efficient post-write reads when the number of dies is large.
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Citations
29 Claims
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1. A method of operating a memory system including an array of non-volatile cells formed along a plurality of bit lines and a plurality of word lines, the word lines each capable of storing one or more pages of data, the method comprising:
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writing multiple pages of data into the array; subsequently reading a plurality of the written pages of data from the array; forming a composite data structure of the plurality of read pages, wherein forming a composite data structure of the plurality of read pages includes performing an exclusive OR operation of the plurality of read pages on a bit line by bit line basis; and performing an evaluation of at least a portion of the composite data structure to determine the presence of high error rate in the plurality of pages of data as written. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification