Non-Volatile Memory Soft Program On-Chip Word Line Grouping
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Solution Overview
Problem
Conventional non-volatile memory devices face challenges in narrowing the threshold voltage distribution range of memory cells during erase and Soft program-On-Chip (SOC) operations, leading to reduced operation characteristics and margins between levels.
Innovation Solution
A method that involves performing a Soft program-On-Chip (SOC) operation for each word line group by grouping word lines and applying incremental soft program voltages, allowing for verification and adjustment to ensure successful programming across all memory cells, thereby narrowing the threshold voltage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional erase operation and SOC operation are performed without word line grouping, then the operation process is simple, but the threshold voltage distribution range of memory cells remains wide
Solution Approach 1:
The patent divides the word lines into multiple groups (first word line group and second word line group) and performs SOC operations separately on each group. This segmentation allows for more precise control of threshold voltage distribution by processing memory cells in smaller, manageable subsets rather than treating all word lines uniformly, thereby narrowing the overall threshold voltage distribution range.
Solution Approach 2:
The patent applies different SOC operation parameters to different word line groups. By tailoring the programming conditions specifically to each word line group's characteristics, the method optimizes threshold voltage distribution locally across different regions of the memory array, achieving a narrower overall distribution while maintaining operational simplicity.
2Reliability
If incremental soft program voltages are applied to all memory cells simultaneously, then the programming speed is fast, but memory cells with different characteristics cannot be properly programmed
Solution Approach 1:
The patent segments memory cells into different groups based on their word line assignments and applies incremental soft program voltages to each group sequentially. This segmentation enables the system to account for variations in memory cell characteristics by processing groups rather than all cells simultaneously, ensuring reliable programming while maintaining efficient throughput.
Solution Approach 2:
The patent dynamically adjusts the soft program voltage levels and application timing based on the specific characteristics of each word line group. By making the programming parameters adaptive rather than fixed, the system achieves both high reliability in programming success and maintained productivity through optimized voltage sequencing.
3Manufacturing precision
If word lines are grouped into multiple groups for SOC operation, then the threshold voltage distribution is narrowed, but the operation time increases
Solution Approach 1:
The patent divides word lines into manageable groups that can be processed in parallel or sequential batches. This segmentation strategy narrows threshold voltage distribution by applying targeted SOC operations to each group while controlling overall operation time through efficient group processing sequences and parallel execution where applicable.
Solution Approach 2:
The patent implements continuous SOC operations across multiple word line groups without unnecessary idle time between groups. By maintaining continuous programming action and optimizing the transition between groups, the system achieves narrowed threshold voltage distribution while minimizing total operation time through sustained useful work.
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
The method effectively reduces the threshold voltage distribution range of memory cells in the erase state, improving operation characteristics and maintaining wider margins between states by ensuring all memory cells are properly programmed.
Implementation Method 1
a NAND-type non-volatile memory device performs a program operation and an erase operation by injecting or discharging charges to or from a floating gate electrode through Fowler-Nordheim (F-N) tunneling
Data Source
AI summary
A method for operating a non-volatile memory device includes performing an erase operation onto a memory block including a plurality of memory cells, and performing a first soft program operation onto all the memory cells of a string, after the erase operation, grouping word lines of the string into a plurality of word line groups, and performing a second soft program operation onto memory cells coupled with the word lines of each word line group.