Non-volatile memory system and data recover read operation method thereof

A nonvolatile memory system comprising:

• a nonvolatile memory device comprising target memory cells, connected to a target wordline, and adjacent memory cells connected to an adjacent wordline adjacent to the target wordline;
• and
• a controller configured to control an operation of the nonvolatile memory device,
• wherein the nonvolatile memory device is configured to perform a first read operation on the adjacent memory cells based on a specific read level and configured to obtain a cell count value for the adjacent wordline,
• wherein the controller is configured to determine offset values for calibrating a normal read level of the target memory cells, by using at least one of an offset table or an algorithm, which defines an optimal offset value based on the cell count value for the adjacent wordline, as a first variable, and further based on a value of additional information, as a second variable, and configured to control the nonvolatile memory device to perform a second read operation on the target memory cells based on the determined offset values and a result of the first read operation,
• wherein the additional information comprises at least one of a program/erase (P/E) cycle of the target memory cells, temperature of the target memory cells, or a location of the target wordline, and
• wherein the offset table includes a plurality of predetermined offset values that respectively match with preset values of the cell count value and at least one of preset values of the P/E cycle of the target memory cells, preset values of the temperature of the target memory cells, or preset values of the location of the target wordline.

A nonvolatile memory device comprising:

• a memory cell array comprising target memory cells, connected to a target wordline, and adjacent memory cells connected to an adjacent wordline adjacent to the target wordline;
• and
• a control logic configured to perform a first read operation based on a specific read level and configured to obtain a cell count value for the adjacent wordline,
• wherein the control logic performs a second read operation on the target memory cells, based on offset values for calibrating a normal read level of target memory cells and a result of the first read operation,
• wherein the offset values are determined by using at least one of an offset table or an algorithm, which defines an optimal offset value based on the cell count value for the adjacent wordline, as a first variable, and further based on a value of additional information, as a second variable,
• wherein the additional information comprises at least one of a program/erase (P/E) cycle of the target memory cells, temperature of the target memory cells, or a location of the target wordline, and
• wherein the offset table includes a plurality of predetermined offset values that respectively match with preset values of the cell count value and at least one of preset values of the P/E cycle of the target memory cells, preset values of the temperature of the target memory cells, or preset values of the location of the target wordline.