Memory Cell Read Voltage Adjustment for Multi-Pass Programming
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Solution Overview
Problem
During multi-pass programming operations in semiconductor memory devices, read errors can occur due to neighboring word line interference and the back pattern effect, which are not effectively addressed by existing technologies.
Innovation Solution
A memory device controller adjusts read voltage levels and sensing timing based on the programming statuses of adjacent memory cells and the open block percentage of the memory block to correct these errors, employing offset voltages and sense time adjustments to minimize read errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multi-pass programming operations are used to program memory cells to multiple data states, then programming capacity and storage density are improved, but read errors occur due to neighboring word line interference and back pattern effects
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the read voltage level based on the programming pass number and the state of neighboring word lines. During multi-pass programming, the read voltage is modified to compensate for the back pattern effect and neighboring word line interference, ensuring accurate sensing despite the changing electrical environment across multiple programming passes.
Solution Approach 2:
The patent implements feedback by using the determined programming statuses of neighboring memory cells to adjust the read voltage for sensing current memory cells. The controller continuously monitors the programming state of adjacent word lines and uses this information to dynamically modify the read voltage, creating a closed-loop system that corrects for interference effects in real-time during multi-pass programming operations.
2Reliability
If read voltage is adjusted based on programming statuses of adjacent memory cells, then read reliability is improved, but device complexity increases due to additional sensing operations
Solution Approach 1:
The patent applies segmentation by dividing the sensing operation into distinct phases corresponding to different programming passes. The read voltage adjustment is segmented based on the specific pass number and the programming state of neighboring word lines, allowing the system to apply targeted corrections without requiring complete redesign of the entire sensing architecture.
Solution Approach 2:
The patent implements dynamics by making the read voltage adjustable and adaptive during the programming operation. Rather than using a fixed read voltage, the system dynamically modifies the read voltage level based on real-time feedback from neighboring cell states, enabling the sensing operation to adapt to changing conditions without requiring complex additional hardware.
Data Source
AI summary
The memory device that includes a memory block memory cells arranged in word lines. A controller is in electrical communication with the memory cells and is configured to program the memory cells to a first set of data states in a first programming pass and then to a greater second set of data states in a second programming pass. During programming of a first set of memory cells in at least one of the first and second programming passes, the controller is further configured to determine programming statuses of a second set of memory cells that is adjacent the first set of memory cells. The controller is further configured to read the first set of memory cells using a read voltage that is adjusted from a base read voltage based on the determined programming statuses of the second set of memory cells.