Nonvolatile Memory Multi-Page Programming Error Correction
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Solution Overview
Problem
Flash memory devices face reliability issues during multi-page data programming due to deterioration of adjacent memory cells when high program voltage is applied, leading to errors and reduced reliability.
Innovation Solution
An operating method for a nonvolatile memory device that programs first page data to memory cells connected to a selected word line, reads previous page data using two sensing values, calculates a fail bit number, and programs the previous page data and remaining page data based on this number to adjacent memory cells, thereby reducing errors and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high program voltage is applied to program multi-page data, then programming speed is improved, but adjacent memory cells deteriorate leading to increased errors
Solution Approach 1:
The patent applies preliminary action by programming page data to unselected word lines before programming to the selected word line. This preliminary programming of adjacent cells allows the system to later read back and verify data, enabling error detection and correction without reducing the overall programming speed advantage of high voltage operations.
Solution Approach 2:
The patent implements feedback by reading back the previously programmed page data from adjacent memory cells and comparing it with the newly programmed data. This feedback mechanism enables the system to detect and correct errors caused by high voltage programming, maintaining data integrity while preserving programming speed.
2Reliability
If page data is programmed to adjacent word lines to avoid deterioration, then reliability is improved, but programming complexity increases
Solution Approach 1:
The system performs preliminary programming of page data to unselected word lines before the main programming operation. This preliminary action simplifies the overall process by pre-positioning data in adjacent cells that can serve as backup or verification storage, reducing the complexity of error handling during the main programming operation.
Solution Approach 2:
The patent merges the programming of multiple word lines into a single operational sequence. By programming adjacent word lines simultaneously or in close succession, the system combines what would otherwise be separate operations into a unified process, reducing overall complexity while maintaining reliability.
3Productivity
If multi-page data is programmed in a single cycle, then productivity is improved, but error rate increases due to adjacent cell deterioration
Solution Approach 1:
The patent applies preliminary action by programming some page data to unselected word lines before the main programming cycle. This preliminary programming creates a buffer that allows the system to detect and correct errors during the same operational cycle, maintaining high throughput while reducing the error rate associated with multi-page data programming.
Solution Approach 2:
The system implements feedback by reading back the preliminary programmed data and comparing it with the final programmed data. This feedback mechanism enables real-time error detection and correction within the programming cycle, allowing the system to maintain both high productivity and low error rates simultaneously.
Data Source
AI summary
An operating method of a nonvolatile memory device for programming multi-page data, the operating method including: receiving the multi-page data from a memory controller; programming first page data among the multi-page data to first memory cells connected to a word line adjacent to a selected word line; reading previous page data previously stored in second memory cells connected to the selected word line based on a first sensing value and a second sensing value after programming the first page data; calculating a first fail bit number by comparing first bits of the previous page data read based on the first sensing value to second bits of the previous page data read based on the second sensing value; and programming the previous page data read from the second memory cells and second page data among the multi-page data to the second memory cells based on the first fail bit number.