Patent ID: 9136022
Filing Date: 2015-09-15
Classification: G06F,G11C

Abstract:
1. A method of operating a three-dimensional nonvolatile memory formed in a plurality of physical levels of memory cells disposed above a substrate, memory cells in the plurality of physical levels connected in series to form vertical NAND strings with memory cells of an individual physical level connected by horizontal word lines, comprising: categorizing the plurality of physical levels in a block into at least a first category and a second category according to memory hole diameter, the first category of physical levels having the smallest memory hole diameter in the block, the second category of physical levels having the largest memory hole diameter in the block; selecting first data assigned to a first word line in a first physical level from the first category of physical levels for an exclusive OR (XOR) operation; selecting second data assigned to a second word line in a second physical level from the second category of physical levels for the XOR operation; and performing the XOR operation on the first data and the second data to generate XOR data.