Bad Block Reconfiguration in Nonvolatile Memory

摘要

When a bad block is found in a nonvolatile memory array, the block is marked as a bad block so that it is not subsequently used. The block is also reconfigured as a bad block by increasing resistance of vertical NAND strings in the block by increasing threshold voltage of at least some transistors along vertical NAND strings, for example, select transistors or memory cell transistors.

主权项

1. A method of operating a plurality of blocks of a three dimensional nonvolatile NAND memory formed as two or more physical levels of memory cells disposed above a substrate comprising:
identifying a block of the plurality of blocks of the three dimensional nonvolatile NAND memory as a bad block; in response to identifying the block as a bad block, recording location information for the bad block to prevent subsequent storage of host data in the bad block; and in response to identifying the block as a bad block, performing a reconfiguration of the block as a bad block by increasing threshold voltages of memory cells of the block and increasing threshold voltages of select transistors of the block.