Nonvolatile Memory Failed Cell Reprogramming via Reinforced Pulses
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Solution Overview
Problem
Nonvolatile memory devices, such as MRAM, face challenges in identifying and reprogramming failed cells due to variations in pulse strength and duration, leading to programming errors and reduced reliability.
Innovation Solution
A method and system for nonvolatile memory that involves programming cells using a normal program pulse, detecting failed cells through verify-read operations, storing information about failed cells in a buffer, and reprogramming them using a reinforced program pulse in an idle state, ensuring accurate data retention and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a normal program pulse is used to program memory cells, then programming speed is maintained, but programming errors occur due to pulse strength variations
Solution Approach 1:
The patent applies parameter changes by switching between normal program pulses and reinforced program pulses based on verification results. When programming failures are detected through verify-read operations, the system changes the pulse parameters (strength and duration) to reinforced levels to successfully program the failed cells, thereby resolving the contradiction between maintaining programming speed and ensuring programming reliability
Solution Approach 2:
The patent implements feedback mechanisms through verify-read operations that check whether memory cells have been successfully programmed. The results of these verification operations feed back into the programming process, triggering reinforced program pulses for failed cells. This closed-loop feedback system ensures reliable programming while maintaining overall programming efficiency
2Reliability
If reinforced program pulses are applied to all memory cells, then programming reliability is improved, but programming time increases
Solution Approach 1:
The patent applies local quality by selectively applying reinforced program pulses only to specific failed memory cells rather than uniformly to all cells. Through verify-read operations, the system identifies which cells require reinforced programming and applies the stronger pulses locally to those cells only, thereby improving reliability without significantly increasing overall programming time
3Measurement precision
If verify-read operations are performed immediately after programming, then failed cells are detected accurately, but operational efficiency decreases
Solution Approach 1:
The patent applies preliminary action by performing verify-read operations immediately after programming to detect failed cells before proceeding to subsequent operations. This preliminary verification ensures accurate identification of failed cells that need reinforced programming, preventing propagation of errors and improving overall data integrity despite the additional time required
Data Source
AI summary
A memory system, and an operation method of a nonvolatile memory, include programming memory cells using a normal program pulse, reading out a first set of data from the memory cells, detecting failed cells based on the first set of data, storing information about the failed cells in a buffer, and reprogramming the failed cells using a reinforced program pulse in an idle state based on the information stored in the buffer.