Magnetic Memory Cell Layout With Multi-Stage Ion Beam Etching

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Solution Overview

Problem

Existing magnetic memory devices face challenges in optimizing the arrangement and manufacturing process of magnetoresistance effect elements to enhance data storage efficiency and reliability.

Innovation Solution

A perpendicular magnetization type magnetic memory device is designed with a specific arrangement of magnetoresistance effect elements and conductors, utilizing a spin injection write system to control magnetization directions, and a precise manufacturing method involving ion beam etching to form rectangular-shaped elements with tapered cross-sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If conventional etching processes are used for magnetoresistance effect elements, then manufacturing simplicity is maintained, but the cross-sectional area and etching efficiency are limited

Engineering Contradiction:

Improvecross-sectional areaVSAvoidetching process complexity

Core Design Contradiction:

Area of moving objectVSEase of manufacture

Solution Approach 1:

The etching process is divided into multiple discrete steps with different etching conditions, allowing each step to optimize for specific requirements. This segmentation enables achieving larger cross-sectional areas while maintaining manufacturing feasibility through controlled multi-stage processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The etching process parameters are dynamically adjusted across different stages, transitioning from conditions favoring high etching speed to conditions favoring high etching precision. This dynamic adaptation resolves the contradiction between area expansion and manufacturing ease.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If discrete ion beam etching is used to increase cross-sectional area, then resistance-area product and magnetoresistance ratio improve, but manufacturing complexity increases

Engineering Contradiction:

Improveetching precisionVSAvoidetching process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The complex etching process is segmented into distinct stages, each with optimized parameters. This segmentation makes the overall complex process more manageable and controllable, achieving high precision while organizing complexity into structured, repeatable steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The etching process employs periodic alternation between different etching conditions, systematically transitioning between speed-optimized and precision-optimized phases. This periodic structure manages process complexity through predictable, cyclical parameter changes.

Inventive Principle:

Principle #19Periodic action

3Reliability

If conventional magnetoresistance effect elements are used, then device simplicity is maintained, but resistance-area product and magnetoresistance ratio are insufficient

Engineering Contradiction:

Improveretention characteristicsVSAvoiddevice structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The magnetoresistance effect element transitions from a conventional planar structure to a vertical pillar structure. This dimensional change increases the effective cross-sectional area and improves retention characteristics while maintaining relatively simple device architecture through vertical integration.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The device structure parameters are changed by forming vertical pillars with optimized dimensions and aspect ratios. This parameter change achieves improved resistance-area product and magnetoresistance ratio while the systematic approach keeps the overall device complexity manageable.

Inventive Principle:

Principle #35Parameter changes

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

This configuration and manufacturing process improve data storage efficiency and reliability by ensuring precise control over resistance states and reducing manufacturing complexity.

Implementation Method 1

discrete ion beam etching

Methodology Applied

Scientific EffectIon beam etching: Ion Beam

Implementation Method 2

magnetoresistance effect element

Methodology Applied

Scientific EffectMagnetoresistance effect: Magnetoresistance

Data Source

PatentUS12484455B2Magnetic memory device and manufacturing method of magnetic memory device

Publication Date: 2025.11.25 KIOXIA CORP

AI summary

According to one embodiment, a magnetic memory device includes a first conductor extending along a first direction, a second conductor extending along a second direction and above the first conductor, and a first layer stack provided between the first conductor and the second conductor and including a first magnetoresistance effect element. The first layer stack has a rectangular shape along a stack surface of the first layer stack. The rectangular shape of the first layer stack has a side intersecting with both the first direction and the second direction.