SENSING PARAMETER MANAGEMENT IN NON-VOLATILE MEMORY STORAGE SYSTEM TO COMPENSATE FOR BROKEN WORD LINES

摘要

Disclosed is a technology to change the parameters by which a read operation is performed in a block with a broken word line. The first method is for reading a broken word line, which may involve changing the voltage on word lines neighboring the broken word line to let the voltage on the broken word line reach the appropriate magnitude through capacitive coupling between word lines. The first method may also involve increasing the time delay before memory cells connected to the broken word line are sensed to allow the voltage on the word line to settle due to increased RC delay. The second method is for reading an unbroken word line in a block with a broken word line, which involves increasing the time delay before memory cells connected to the unbroken word line are sensed while raising the voltages on the word lines neighboring the broken word line.

主权项

1. A method to recover data from non-volatile memory, comprising:
concluding that a particular word line is broken, the particular word line is connected to a set of non-volatile storage elements; applying a low voltage to the particular word line; applying a recovery pass voltage to a first neighbor word line that is adjacent to the particular word line, the recovery pass voltage is lower than a standard neighbor pass voltage normally applied to the first neighbor word line when reading the set of non-volatile storage elements if the particular word line is not broken, the recovery pass voltage on the first neighbor word line will couple to the particular word line and raise a voltage on the particular word line to a level above a read voltage; after a first time delay to allow the voltage on the particular word line to decrease towards the low voltage, applying the read voltage to the particular word line; and after a second time delay that is subsequent to the first time delay and allows for the voltage on the particular word line to decrease towards the read voltage, sensing bit lines connected to the set of non-volatile storage elements, the second time delay is longer than if the particular word line is not broken.