Memory Block Programming to Close Grown Bad Block Leakage
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Solution Overview
Problem
Current non-volatile storage devices face the risk of double memory block selection when a memory block is identified as a grown bad block, leading to failed write operations and potential read-only mode due to shared bit lines with good blocks.
Innovation Solution
A bad block management system initiates a manual block write process on the wordlines of identified grown bad blocks, programming them with higher voltages to close the leakage path between the bit line and ground line, preventing current flow and ensuring correct block selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grown bad block is marked as fail state and left open, then the memory block can be identified as failed, but the leakage path remains open causing double block selection risk
Solution Approach 1:
The patent converts the harmful leakage path in grown bad blocks into a beneficial feature by intentionally programming specific wordlines to create controlled leakage paths. This programmed leakage actually prevents double block selection by creating a distinguishable electrical characteristic that allows the controller to identify and exclude bad blocks during selection, thus transforming the harmful leakage into a useful identification mechanism.
Solution Approach 2:
The patent changes the electrical parameters of the grown bad block by programming specific wordlines with different voltage levels than normal blocks. This creates distinct electrical characteristics (different threshold voltages, different leakage currents) that allow the controller to differentiate between good and bad blocks during selection, thereby eliminating the double block selection problem while maintaining reliable bad block identification.
2Reliability
If higher voltage is applied to program wordlines in grown bad blocks, then the leakage path is closed more effectively, but the energy consumption increases
Solution Approach 1:
The patent applies higher programming voltages only to specific wordlines associated with grown bad blocks, rather than uniformly increasing voltage across all memory blocks. This localized application of high voltage closes the leakage path in bad blocks without significantly increasing overall energy consumption, as only a subset of wordlines requires the elevated voltage treatment.
3Reliability
If a manual block write process is initiated on grown bad blocks, then the leakage path is closed and double block selection is prevented, but the processing time increases
Solution Approach 1:
The patent performs the manual block write process on grown bad blocks during initial characterization or at the first opportunity, rather than waiting for problems to occur. By proactively closing the leakage path and programming the wordlines early in the bad block identification process, the system prevents future double block selection issues without adding time to subsequent operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively neutralizes the risk of double block selection, enhancing the reliability of the memory device by ensuring proper voltage distribution and reducing the likelihood of entering a read-only mode.
Implementation Method 1
programming them with higher voltages to close the leakage path between the bit line and ground line, preventing current flow
Data Source
AI summary
A data storage device includes a bad block management system. The bad block management system detects a grown bad block of the data storage device. When a grown bad block is detected, the bad block management system initiates a manual block write process on the wordlines associated with the grown bad block. The manual block write process includes programming the wordlines of the grown bad block in a particular state and with a voltage that closes a leakage path between a bit line associated with the grown bad block and a ground line or a ground path associated with the grown bad block.