Memory Word Line Grouping for Threshold-Aware Read Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing number of word lines per block in semiconductor memory devices leads to varying threshold voltage distributions, causing read disturbances and differing read characteristics, which complicates successful data retrieval.
Innovation Solution
A storage apparatus that groups word lines based on similar threshold voltage distributions and applies a representative read voltage to each group, optimizing read performance by adjusting group sizes to meet a set tolerance value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of word lines per block is increased to scale down chip size, then chip size is reduced, but read disturbance increases and read characteristics vary
Solution Approach 1:
The patent divides the word lines into multiple groups based on their threshold voltage distributions. Each group is assigned a representative read voltage that is optimized for that specific group. This segmentation allows different word lines with different threshold voltage characteristics to be read using appropriate voltages, reducing read disturbance and improving read success while maintaining high word line density per block.
2Reliability
If read retry method is applied to cope with threshold voltage variation, then read reliability is improved, but read time increases
Solution Approach 1:
The patent performs preliminary grouping of word lines according to their threshold voltage distributions before read operations. By pre-organizing word lines into groups with similar threshold voltage characteristics and assigning representative voltages in advance, the system eliminates the need for time-consuming read retry operations during actual read tasks, thus improving reliability without increasing read time.
3Reliability
If word lines are grouped by threshold voltage distribution, then read performance is improved, but device complexity increases
Solution Approach 1:
The patent employs self-service mechanisms where the memory device automatically performs threshold voltage measurement and word line grouping without external intervention. The system uses built-in circuits to measure threshold voltages, determine optimal groupings, and store grouping information in lookup tables. This automation reduces the complexity burden on external control systems while maintaining high read performance.
Data Source
AI summary
A storage apparatus includes a memory device including a plurality of word lines; and a word line grouping device configured to group the plurality of word lines into a certain number of groups each serving as a memory block so that a read performance value, obtained by reading data of word lines included in a same group by using a representative read voltage, is satisfied with a set tolerance value.