Western Digital Technologies, Inc.

Sandisk Technologies Inc.

Wenkai Liu

Liang Li

Yan Li

Xiaohu Liu

Cuili Fu

In a word line leakage detection process in a NAND or other non-volatile memory device, to determine leaky blocks of a memory device, a reference value for block is determined by comparing the current drawn by the peripheral circuitry of the block with a sequence of comparison current values, corresponding to a range of digital values, while the peripheral circuit is not connected to the block. The current drawn when the peripheral circuitry is connected to the block is then determined, again by comparison with a sequence of comparison values, but of a reduced range of digital values, running from an offset above the reference value to an offset below the reference value. To further reduce test times, the same reference value is used for a group of blocks, such as groups of blocks that share a set of supply lines.

Self-learning built-in self-test (BIST) for leak detection in non-volatile memory

A memory die assembly, comprising a non-volatile memory structure, performs autonomous testing of the memory die assembly by repeatedly performing a group of tests for multiple cycles such that the group of tests includes programming, erasing and reading the non-volatile memory structure. Failure events from the tests are recorded by storing error data for each recorded failure event including a location in the non-volatile memory structure of the failure event, a type of test that failed and a cycle during which the failure event occurred.

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Shanghai, China

Wenkai Liu