Memory Device Read Voltage Control for Interference Reduction

Solution Overview

Problem

In memory devices, particularly those with three-dimensional structures, the close spacing of word lines leads to interference phenomena during read operations, causing threshold voltage distribution deterioration and read disturbance, which existing solutions attempt to mitigate by increasing pass voltages but result in further disturbances.

Innovation Solution

Applying specific pass voltages to unselected word lines based on the read voltage applied to the selected word line, with different pass voltages for memory cells with threshold voltages higher or lower than a reference voltage, to improve read disturbance and interference management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If pass voltage is increased to reduce read disturbance, then read disturbance is reduced, but further disturbances occur

Engineering Contradiction:

Improveread disturbanceVSAvoiddisturbance

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent applies different pass voltages to different unselected word lines based on their specific characteristics and interference levels. Instead of using a uniform high pass voltage that causes disturbances, the system selectively applies appropriate voltages to minimize read disturbance while preventing interference, thereby resolving the contradiction between reducing read disturbance and avoiding generation of new disturbances.

Inventive Principle:

Principle #3Local quality

2Productivity

If word lines are closely spaced to improve integration, then integration is improved, but interference phenomena occur

Engineering Contradiction:

ImproveintegrationVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent dynamically adjusts pass voltages based on the specific word lines being operated on. The system determines appropriate pass voltages in real-time during read operations, allowing close word line spacing for high integration while preventing interference through adaptive voltage control, thus resolving the contradiction between integration and interference.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If multiple read voltages are applied to distinguish program states, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveprogram state determinationVSAvoidvoltage control

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies different pass voltages to different unselected word lines based on their specific characteristics and interference levels. Instead of using a uniform high pass voltage that causes disturbances, the system selectively applies appropriate voltages to minimize read disturbance while preventing interference, thereby resolving the contradiction between reducing read disturbance and avoiding generation of new disturbances.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12190956B2Memory device and method of operating the memory device

Publication Date: 2025.01.07 SK HYNIX INC

AI summary

A memory device including a plurality of memory cells, a peripheral circuit configured to perform a read operation of reading data from memory cells connected to a selected word line, and a read operation controller configured to apply a plurality of read voltages to the selected word line, apply a first pass voltage to unselected word lines while first read voltages for determining a program state of memory cells having a threshold voltage higher than a reference voltage among the plurality of read voltages are applied to the selected word line, and apply a second pass voltage higher than the first pass voltage to the unselected word line while second read voltages for determining a program state of memory cells having a threshold voltage lower than the reference voltage among the plurality of read voltages are applied to the selected word line.