Memory management method, memory storage device and memory control circuit unit

摘要

A memory management method, a memory storage device and a memory control circuit unit are provided. The method comprises: obtaining a first threshold voltage distribution of memory cells; grouping the first threshold voltage distribution to a plurality of first threshold voltage groups; obtaining a second threshold voltage distribution of the memory cells; grouping the second threshold voltage distribution to a plurality of second threshold voltage groups; allocating a memory cell among the memory cells to a virtual block if a threshold voltage pair of the memory cell belongs to a specific group of the first threshold voltage groups and a specific group of the second threshold voltage groups, such that the first memory cell is operated under a specific-level cell mode. Accordingly, the reliability of memory cells may be improved without significantly sacrificing the capacity of the rewritable non-volatile memory module.

主权项

1. A memory management method for a rewritable non-volatile memory module comprising a plurality of memory cells, and the memory management method comprising:
obtaining a first threshold voltage distribution of the memory cells; grouping the first threshold voltage distribution of the memory cells to a plurality of first threshold voltage groups; obtaining a second threshold voltage distribution of the memory cells; grouping the second threshold voltage distribution of the memory cells to a plurality of second threshold voltage groups, wherein a terminal threshold voltage of the first threshold voltage groups is lower than a terminal threshold voltage of the second threshold voltage groups; allocating a first memory cell among the memory cells to a first virtual block if a first threshold voltage pair of the first memory cell belongs to a first group of the first threshold voltage groups and a first group of the second threshold voltage groups, such that the first memory cell is operated under an M-level cell mode; and allocating a second memory cell among the memory cells to a second virtual block if a second threshold voltage pair of the second memory cell belongs to a second group of the first threshold voltage groups and a second group of the second threshold voltage groups, such that the second memory cell is operated under an N-level cell mode, wherein a terminal threshold voltage of the second group of the first threshold voltage groups is lower than a terminal threshold voltage of the first group of the first threshold voltage groups, wherein a terminal threshold voltage of the second group of the second threshold voltage groups is higher than a terminal threshold voltage of the first group of the second threshold voltage groups, wherein M and N are both positive integers and larger than 1, and N is larger than M.