Systems And Methods For Read Disturb Management In Non-Volatile Memory

摘要

Non-volatile memory and methods of reading non-volatile memory are provided for managing and reducing read related disturb. Techniques are introduced to reduce read disturb using state-dependent read pass voltages for particular word lines during a read operation. Because of their proximity to a selected word line, adjacent word lines can be biased using state-dependent pass voltages while other unselected word lines are biased using a standard or second set of pass voltages. Generally, each state-dependent pass voltage applied to a word line adjacent to the selected word line is larger than the second set of pass voltages applied to other unselected word lines, although this is not required. Other word lines, may also be biased using state-dependent pass voltages. System-level techniques are provided with or independently of state-dependent pass voltages to further reduce and manage read disturb. Techniques may account for data validity and memory write and erase cycles.

主权项

1. A method of reading non-volatile storage, comprising:
applying a set of read voltages to a selected word line as part of reading data from a set of non-volatile storage elements coupled to the selected word line, the set of read voltages including a first read voltage, a second read voltage, and a third read voltage; applying to a first unselected word line that is adjacent to the selected word line a first set of state-dependent pass voltages, the first set of state-dependent pass voltages including a first pass voltage that is applied while applying the first read voltage, a second pass voltage that is applied while applying the second read voltage, and a third pass voltage that is applied while applying the third read voltage, the first pass voltage is greater than the second pass voltage and the second pass voltage is greater than the third pass voltage; and applying to a second unselected word line a fourth pass voltage corresponding to the set of read voltages, the fourth pass voltage being less than the first pass voltage and the second pass voltage, the fourth pass voltage being less than or equal to the third pass voltage.