Patent ID: 9741440
Date: 2017-08-22
CPC Classifications: G11C

Claim:
1. A method of reading a three-dimensional memory cell array, the cell array including a plurality of memory blocks, each memory block including a plurality of word-lines, the plurality of word-lines comprising a boundary word-line, a program region, and a erase region, the boundary word-line being a word-line last programmed in the memory block, the program region being a first group of the plurality of word-lines which are programmed excepting the boundary word-line, and the erase region being a second group of the plurality of word-lines which are not programmed, the method comprising: receiving a read command to perform a read operation, the read command including a read address for selecting a read word-line; determining the read word-line as one of the boundary word-line, a programmed word-line and an erased word-line, the programmed word-line being one of the first group and the erased word-line being one of the second group; performing the read operation with a first word-line voltage if the read word-line is determined to be the programmed word-line; and performing the read operation with a second word-line voltage if the read word-line is determined to be the boundary word-line, wherein the second word-line voltage is smaller than the first word-line voltage.