Nonvolatile Memory Wordline Coupling for Read Failures
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Solution Overview
Problem
Nonvolatile memory devices face performance degradation and increased firmware complexity due to no-coupled wordlines, which lead to default read failures and resource inefficiencies.
Innovation Solution
A method is introduced where a nonvolatile memory device performs a second program operation on adjacent wordlines without a data write command, converting no-coupled wordlines into coupled wordlines, thereby preventing performance degradation and reducing firmware overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a first program operation is performed on some wordlines based on a data write command, then data is written to the memory device, but no-coupled wordlines are created causing performance degradation and increased firmware complexity
Solution Approach 1:
The patent performs a second program operation on adjacent open wordlines before read operations are needed. This preliminary action converts no-coupled wordlines into coupled wordlines in advance, eliminating the need for complex firmware handling during subsequent read operations and preventing performance degradation.
Solution Approach 2:
The patent converts the harmful effect of no-coupled wordlines (which cause read failures and performance degradation) into a benefit by performing dummy program operations on adjacent open wordlines. This transforms the problematic open state into a beneficial coupled state, eliminating firmware complexity and improving read performance.
2Reliability
If no-coupled wordlines are left open after program operation, then resources are preserved, but read failures occur and performance degrades
Solution Approach 1:
The patent performs dummy program operations on adjacent open wordlines before read operations occur. This preliminary coupling of wordlines ensures that when reads are performed, all necessary wordlines are properly coupled, preventing read failures while maintaining operational efficiency through automated control.
3Reliability
If firmware is designed to handle no-coupled wordlines, then read failures are prevented, but firmware overhead increases
Solution Approach 1:
The patent implements self-service by having the memory device automatically perform dummy program operations on adjacent open wordlines without external firmware intervention. The control circuit detects no-coupled wordlines and autonomously couples them by programming adjacent open wordlines, eliminating the need for complex firmware handling logic.
Solution Approach 2:
The control circuit performs preliminary coupling of wordlines by executing dummy program operations before read operations are needed. This advance preparation ensures read reliability is maintained while keeping firmware simple, as the coupling action is automated within the memory device itself.
4Reliability
If all wordlines are programmed to avoid no-coupled wordlines, then read performance is maintained, but write efficiency decreases
Solution Approach 1:
The patent applies local quality by performing dummy program operations only on adjacent open wordlines that are locally affected by no-coupled conditions, rather than programming all wordlines globally. This localized approach maintains read performance in affected areas while preserving write efficiency by avoiding unnecessary programming operations elsewhere.
Solution Approach 2:
The patent uses partial action by performing dummy program operations only on the specific adjacent open wordlines that need coupling, rather than programming all wordlines. This selective approach provides sufficient coupling action to prevent read failures while minimizing unnecessary programming overhead and maintaining write efficiency.
Data Source
AI summary
In a method of operating a nonvolatile memory device, the nonvolatile memory device includes a memory block that includes a plurality of memory cells and is connected to a plurality of wordlines. A data write command is received. Based on the data write command, a first program operation is performed on some wordlines among the plurality of wordlines connected to the memory block. At least one of the some wordlines on which the first program operation is performed is detected as a no-coupled wordline. Without the data write command, a second program operation is performed on an open wordline on which the first program operation is not performed and adjacent to the no-coupled wordline.