Nonvolatile Memory Bad Block Detection via Dummy Voltage
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Solution Overview
Problem
Nonvolatile memory devices face data loss due to word line bridging phenomena, which occur as the number of layers in 3D memory cell arrays increases, leading to uncorrectable errors and data loss, as the insulating layer between word lines is destroyed, causing shorts and making it difficult to detect bad blocks effectively.
Innovation Solution
The nonvolatile memory device employs a control logic circuit to generate a dummy verifying voltage and detection count based on the pump voltage and reference voltage, allowing it to predict and set memory blocks as bad blocks, thereby preventing data loss by identifying and replacing faulty memory blocks before they cause errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of layers in 3D memory cell arrays is increased to improve storage capacity, then the storage density is improved, but the insulating layer between word lines is destroyed causing word line bridging and data loss
Solution Approach 1:
The patent applies preliminary action by performing a detection operation before the memory block is actually used for data storage. A dummy verifying voltage is applied to detect potential word line bridging issues in advance, allowing the system to identify and mark bad blocks before they cause data loss, thus preventing the reliability problem while maintaining high storage capacity
Solution Approach 2:
The patent applies preliminary anti-action by proactively counteracting the potential word line bridging phenomenon through detection. By applying a dummy verifying voltage and detecting abnormal current flow before actual data operations, the system neutralizes the reliability threat that would otherwise occur during normal high-density storage operations
2Device complexity
If traditional detection methods are used for bad blocks, then the device complexity is low, but the ability to detect word line bridging issues is insufficient leading to undetected bad blocks
Solution Approach 1:
The patent introduces an intermediary detection mechanism that uses a dummy verifying voltage as a mediator to indirectly detect word line bridging issues. Instead of directly monitoring for bridging, the system uses this intermediary voltage to provoke a response (abnormal current flow) that reveals the presence of bridging, thereby improving detection accuracy without significantly increasing complexity
Solution Approach 2:
The patent replaces traditional mechanical or direct electrical detection methods with an electrical field-based detection approach. By using a dummy verifying voltage to create an electric field that interacts with potential bridging paths, the system achieves more precise detection of insulation failures without adding complex mechanical detection structures
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 detects and prevents data loss by identifying memory blocks with word line bridging issues, ensuring data integrity and maintaining correct bit values by setting bad blocks, thus reducing uncorrectable errors and maintaining data reliability.
Implementation Method 1
applying, using the control logic circuit, a dummy verifying voltage generated by regulating a first pump voltage of a first charge pump to the first word line
Implementation Method 2
generating, using the control logic circuit, a first detection count based on the first pump voltage and a first reference voltage, and outputting, using the control logic circuit, a bad block setting signal for setting the first memory block as a bad block based on the first detection count and a first reference count
Data Source
AI summary
Provided is a nonvolatile memory device and an operating method thereof. The operating method for programming a first memory block from among a plurality of memory blocks includes: programming a first word line connected to the first memory block by sequentially executing first to Nth (N is a natural number) programming loops; applying a voltage generated by regulating a first pump voltage of a first charge pump to the first word line as a dummy verifying voltage after the programming is completed; generating a first detection count based on the first pump voltage and a first reference voltage; and outputting a bad block setting signal for setting the first memory block as a bad block based on a result of comparing the first detection count with the first reference count.