Solid state storage device and patrol read method using word line groupings thereof

Abstract

A solid-state storage device is provided, which includes a controller and a non-volatile memory. The controller selects a first word line group from a plurality of word line groups obtained by classifying the word lines based on a read threshold voltage of each word line, and a representative word line corresponding to each word line group is set based on the read threshold voltage associated with each word line group. The controller uses the read threshold voltage of a first representative word line corresponding to the first word line group to read page data of the first representative word line. When the controller cannot correctly read the page data of the first representative word line using the read threshold voltage of the first representative word line, the controller updates the read threshold voltage of the first representative word line in the first word line group.