Semiconductor Memory Device Status Fail Signal Verification
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Solution Overview
Problem
Semiconductor memory devices face reliability issues due to repeated programming operations on memory cells, which can damage existing data and degrade memory cell reliability, especially when the same cells are programmed multiple times without proper verification.
Innovation Solution
A method and device for operating semiconductor memory devices that involve receiving a program command, performing a program operation by increasing threshold voltages of selected memory cells, reading page data, and determining the number of cells that have successfully passed the program operation. If the number of successful cells is below a certain threshold, a status fail signal is output, and the operation is repeated until the desired number of cells meets a critical value, ensuring accurate programming without damaging existing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated program operations are performed on memory cells to ensure programming completeness, then programming reliability is improved, but memory cell damage and data degradation increase
Solution Approach 1:
The patent performs a program operation verification step before initiating repeated programming operations. By first determining whether the number of memory cells passing the program operation exceeds a determined number, the system performs a preliminary assessment to decide whether repeated operations are necessary, thereby avoiding unnecessary programming that would damage memory cells.
Solution Approach 2:
The patent implements a feedback mechanism where the result of the program operation (number of passing cells) is used to determine whether to repeat the programming operation. This feedback loop allows the system to adaptively control the programming process, repeating only when necessary and stopping when the determined number condition is met, thus preventing excessive programming damage.
2Reliability
If program operation is repeated to program all memory cells, then programming completeness is improved, but time consumption increases
Solution Approach 1:
The patent performs a preliminary program operation and verification to determine whether repeated operations are needed. This preliminary action prevents unnecessary repeated programming operations, thereby reducing time consumption while ensuring programming completeness only when required.
Solution Approach 2:
The patent applies partial action by performing repeated program operations only when the number of passing cells does not exceed the determined number. This partial repeated action (only when necessary) rather than full repeated action (always) optimizes the balance between programming completeness and time consumption.
3Measurement precision
If verification is performed after each program operation, then programming accuracy is improved, but operation complexity increases
Solution Approach 1:
The patent uses a feedback mechanism where the verification result (number of passing cells) directly controls the next operation. This simple feedback loop improves programming accuracy through verification while keeping operation complexity low by using the verification result to make straightforward decisions about whether to repeat the program operation.
Data Source
AI summary
In a method of operating a semiconductor memory device, a program command is received, and a program operation is performed to increase threshold voltages of memory cells to be programmed by applying a program pulse to a word line. Page data is read from the selected memory cells by applying a verification voltage to the word line, and it is determined whether the number of memory cells corresponding to a program pass is greater than a determined number, based on the page data. A status fail signal is output based on the determination result.