US 2024/0403178 A1 · ADAPTIVE WORD LINE STRESS FOR LEAK DETECTION IN NON-VOLATILE MEMORY

Abstract

In a word line leakage detection process in a NAND or other non-volatile memory device, a stress selected set of word lines have a high stress voltage applied while other parts of an array are biased to a low level. While stressing the memory array, the current drawn by the array is compared to a leakage detection current that increases in amplitude. For example, this can be done by mirroring the array current and comparing this with the current from a current source that increases in response to a digital input value and determining when it exceeds the mirror current, at which point the stress is discontinued. In addition to determining the amount of leakage, this approach results in low leakage word lines receiving less stress, while greater leakage result in greater amounts of stress being applied.

Claims20

Dependent claims

A non-volatile memory system, comprising:

a control circuit configured to connect to one or more arrays each comprising a plurality of non-volatile memory connected along word lines, the control circuit configured to:
concurrently apply a set of stress bias voltages to one or more selected arrays, where to apply the set of stress bias voltages the control circuit is further configured to:
apply a high stress voltage to one or more selected word lines of the one or more selected arrays;
and
bias other elements of the one or more selected arrays to a low voltage level;
generate a comparison current having an increasing value as a function of time over a comparison interval;
compare, during the comparison interval, a current drawn by the one or more selected arrays in response to the set of stress bias voltages, including a leakage current, with the comparison current;
and
based on the comparison, determine whether the one or more selected arrays exhibit excessive leakage.

6 more elements

A non-volatile memory system, comprising:

an array of non-volatile memory cells connected along word lines;
and
one or more control circuits connected to the array, the one or more control circuits configured to:
stress the array for an interval having a duration dependent upon an amount of leakage current from the word lines in response to the stressing, the duration of the interval increasing in response to the amount of leakage being higher and the stressing comprising, where, to stress the array, the one or more control circuits are configured to:
apply a high voltage level to one or more stress selected word lines;
and
concurrently with applying the high voltage level to the stress selected word lines, bias other elements of the array to a low voltage level;
determine an amount of current, including the leakage current, drawn by the array in response to the stressing;
and
determine whether the array is defective based upon the amount of current drawn by the array in response to the stress.

7 more elements

Dependencies are inferred from the claim text.

Adaptive word line stress for leak detection in non-volatile memory

Life of this patent

Adaptive word line stress for leak detection in non-volatile memory

Life of this patent

Abstract

Claims20