Word Line Driving Direction Control for Memory Cell Interference

Solution Overview

Problem

Interference between memory cells in nonvolatile memory devices occurs due to the narrowing of distances between cells, and there is a trade-off between data retention without power and data processing speed.

Innovation Solution

A semiconductor device with a memory cell array and control circuit that unidirectionally drives unselected word lines and bidirectionally drives selected word lines based on address signals, reducing interference by controlling the driving directions of word lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If multiple memory cells are formed by cutting one hole to increase density, then memory cell density is improved, but interference between memory cells increases due to narrowed distances

Engineering Contradiction:

Improvememory cell densityVSAvoidinterference between memory cells

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent segments the word line driving into multiple independent line driving circuits (first line driving circuit and second line driving circuit), each controlling specific memory strings (first memory strings and second memory strings respectively). This segmentation allows independent control of voltage signals applied to adjacent memory cells, thereby reducing interference while maintaining high density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different driving strategies to different word lines based on their selection status: unselected word lines are driven unidirectionally (only in the first direction) while selected word lines are driven bidirectionally. This local differentiation in driving quality reduces interference between adjacent memory cells while ensuring proper operation of selected cells.

Inventive Principle:

Principle #3Local quality

2Reliability

If unselected word lines are driven bidirectionally to ensure complete voltage application, then data retention is improved, but interference between adjacent memory cells increases

Engineering Contradiction:

Improvedata retentionVSAvoidinterference between memory cells

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different driving strategies to different word lines based on their selection status: unselected word lines are driven unidirectionally (only in the first direction) while selected word lines are driven bidirectionally. This local differentiation in driving quality reduces interference between adjacent memory cells while ensuring proper operation of selected cells.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

For unselected word lines, the patent applies partial action by driving them only in the first direction rather than bidirectionally. This sufficient but not excessive driving approach maintains data retention for unselected cells while minimizing interference with adjacent memory strings.

Inventive Principle:

Principle #16Partial or excessive action

3Object-affected harmful factors

If multiple line driving circuits are used to control different memory strings independently, then interference between memory cells is reduced, but device complexity increases

Engineering Contradiction:

Improveinterference between memory cellsVSAvoidnumber of line driving circuits

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the word line driving into multiple independent line driving circuits (first line driving circuit and second line driving circuit), each controlling specific memory strings (first memory strings and second memory strings respectively). This segmentation allows independent control of voltage signals applied to adjacent memory cells, thereby reducing interference while maintaining high density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each line driving circuit is designed with multi-functionality to control multiple word lines (both selected and unselected) within its designated group. This universality reduces the need for separate dedicated control circuits for each word line, thereby managing complexity while maintaining independent control capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20260045303A1Semiconductor device and operating method for controlling driving direction of word line

Publication Date: 2026.02.12 SK HYNIX INC

AI summary

A semiconductor device may include a memory cell array including a first memory string that is connected to a first drain selection line and a second memory string that is connected to a second drain selection line, a control circuit configured to generate a first switch control signal and a second switch control signal based on an address signal, a first switch disposed in a direction corresponding to the first drain selection line and configured to connect a global word line with a local word line or disconnect the global word line from the local word line based on the first switch control signal, and a second switch disposed in a direction corresponding to the second drain selection line and configured to connect the global word line with the local word line or disconnect the global word line from the local word line based on the second switch control signal.