Non-volatile memory device and operating method thereof

An operating method of a non-volatile memory device, the method comprising:

• performing a test read operation using a virtual negative read (VNR) scheme on a memory cell block defined to include a plurality of memory cell groups;
• setting an offset voltage by comparing an actually raised threshold voltage value of each memory cell group measured according to the result of the test read operation with a target threshold voltage value of each memory cell group intended to be raised according to the VNR scheme;
• and
• setting a new read voltage by adding the offset voltage to a read voltage used in the test read operation.

An operating method of a non-volatile memory device, the method comprising:

• programming a memory block defined to include a plurality of memory cell groups;
• performing a test read operation using a virtual negative read (VNR) scheme on each memory cell group of the memory block;
• setting an offset voltage by comparing an actually raised threshold voltage value of each memory cell group measured according to the result of the test read operation with a target threshold voltage value of each memory cell group intended to be raised according to the VNR scheme;
• setting a new read voltage corresponding to each memory cell group by using an offset voltage set by memory cell group according to the test read operation;
• and
• performing a read operation by memory cell group of the memory block by using the new read voltage.