Patent ID: 7573773

Claim:
A reprogrammable non-volatile memory system, comprising: a plurality of charge storage memory cells connected in a plurality of strings that individually contain a plurality of series connected memory cells, the strings being individually connectable at first and second ends thereof to respective first and second voltage sources and having word lines extending in a direction across the plurality of strings to individually define pages of memory cells, and a controller connected with the charge storage memory cells and that operates to: designate at least those pages of memory cells immediately adjacent the first and second ends of the strings to be vulnerable to being disturbed during execution of a commanded data read from pages of memory cells not immediately adjacent the ends of the strings, recognize when pages of memory cells not immediately adjacent the ends of the strings have been accessed and data stored in the accessed pages of memory cells read in response to a command, subsequently initiate a scrub read of data from at least some of the pages of memory cells immediately adjacent the first and second ends of the strings, determine a level of quality of the scrub read data and whether it is adequate, and if the level of quality of the read data is determined not to be adequate, refresh the data stored in the at least some of the pages of memory cells immediately adjacent the first and second ends of the strings.