Dynamic Pass Voltage Adjustment for Non-Volatile Memory Programming
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Solution Overview
Problem
Existing non-volatile memory devices face challenges in accurately programming memory cells due to performance variations caused by cycling and differences among memory cells, leading to issues like program disturb and inefficient voltage control.
Innovation Solution
The implementation of multi-pass programming techniques that adjust both initial program voltage and pass voltage based on current memory cell performance, using a combination of sense blocks and control circuitry to optimize programming by dynamically selecting voltages and adjusting them according to the performance level of the memory cells, thereby minimizing capacitive coupling effects and achieving narrow threshold voltage distributions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed voltage programming is used, then device complexity is reduced, but manufacturing precision deteriorates due to performance variations
Solution Approach 1:
The patent implements dynamic voltage adjustment by modifying both the initial program voltage and pass voltage based on detected programming speed. The control circuit changes voltage levels in real-time during the programming process, transitioning from fixed to dynamic voltage control to achieve narrow threshold voltage distributions while accounting for cell performance variations.
Solution Approach 2:
The patent changes voltage parameters (initial program voltage and pass voltage) based on detected programming speed characteristics. By adjusting these voltage parameters according to actual cell performance, the system achieves precise threshold voltage control without requiring overly complex fixed-voltage control mechanisms.
2Reliability
If higher pass voltage is applied to minimize program disturb, then reliability improves, but device complexity increases due to voltage adjustment mechanisms
Solution Approach 1:
The patent employs feedback mechanisms where the control circuit detects programming speed during the programming process and uses this information to adjust pass voltage levels. This closed-loop feedback ensures reliable programming by adapting pass voltage to actual cell conditions, minimizing program disturb while avoiding excessive complexity through efficient feedback utilization.
3Manufacturing precision
If multi-pass programming with voltage adjustment is implemented, then manufacturing precision improves, but productivity decreases due to additional programming passes
Solution Approach 1:
The patent applies partial voltage adjustments in multi-pass programming, where not all voltage parameters are changed in every pass. By selectively adjusting initial program voltage and pass voltage based on detected programming speed, the system achieves narrow threshold voltage distributions while minimizing the impact on overall programming throughput through targeted rather than exhaustive adjustments.
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 minimizes program disturb and ensures accurate programming by adapting voltage settings to the specific performance of memory cells, improving data retention and reducing failures due to scaling and cycling effects.
Implementation Method 1
determining a programming speed-indicating program voltage of a first set of step-wise increasing program voltages applied to a selected word line... minimizing capacitive coupling effects
Data Source
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AI summary
A programming techniques adaptively sets a pass voltage and an initial program voltage based on a programming speed of a set of memory cells. In one pass of a multi-pass programming operation, a programming speed-indicating program voltage is obtained. For example, this can be a final program voltage or a program voltage at another programming milestone. A pass voltage is determined for another programming pass of the multi-pass programming operation, by providing an adjustment to a reference pass voltage. An initial program voltage is determined for the another programming pass based on an offset from the programming speed-indicating program voltage. The initial program voltage is further adjusted to counteract an effect of the adjustment to a reference pass voltage. The adjustment to the initial program voltage is opposite in polarity and smaller in magnitude than the adjustment to the reference pass voltage.