Magnetic Shield with In-Plane Magnetization for MRAM

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Solution Overview

Problem

Magnetic shields with perpendicular anisotropy struggle to achieve sufficient magnetic permeability and shielding properties due to interference from diamagnetic fields, leading to inadequate protection against external magnetic fields in magnetoresistive memories.

Innovation Solution

A magnetic shield with in-plane magnetization and imparted perpendicular magnetic anisotropy is used, allowing it to generate a perpendicular magnetization component when exposed to an external magnetic field, thereby enhancing its permeability and shielding effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetic shield with perpendicular anisotropy is used, then the magnetization direction can be controlled, but the diamagnetic field interrupts the change in magnetization in the perpendicular direction, reducing magnetic permeability and shielding effectiveness

Engineering Contradiction:

Improveshielding effectivenessVSAvoidmagnetic permeability

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent changes the magnetization direction parameter from perpendicular to in-plane, and modifies the anisotropy type from perpendicular magnetic anisotropy to in-plane magnetic anisotropy. This parameter change eliminates the diamagnetic field interference that occurs in perpendicular anisotropy structures, thereby improving both magnetic permeability and shielding effectiveness simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of attempting to overcome the diamagnetic field interference in perpendicular anisotropy structures, the invention inverts the approach by using in-plane magnetization with in-plane anisotropy. This inverted configuration naturally avoids the diamagnetic field issue while achieving the desired shielding performance

Inventive Principle:

Principle #13The other way round (Inversion)

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 magnetic shield effectively absorbs magnetic flux and reduces the magnetic field density around magnetoresistive memories, improving shielding properties in both perpendicular and in-plane directions.

Implementation Method 1

the perpendicular magnetic anisotropy is imparted to the magnetic shield

Methodology Applied

Scientific EffectPerpendicular magnetic anisotropy: Anisotropy

Implementation Method 2

achieve a sufficient magnetic permeability with respect to the external magnetic field in the perpendicular direction

Methodology Applied

Scientific EffectMagnetic permeability: Magnetism

Implementation Method 3

the change in magnetization in its perpendicular direction is interrupted by the influence of diamagnetic field acting in the thickness direction of the magnetic shield

Methodology Applied

Scientific EffectDiamagnetic field: Diamagnetism

Data Source

PatentUS10305024B2Semiconductor package

Publication Date: 2019.05.28 RENESAS ELECTRONICS CORP

AI summary

Provided is a magnetic shield having improved shielding properties from an external magnetic field. A magnetic shield MS1 has in-plane magnetization as remanent magnetization, and is adapted to generate a perpendicular component in the magnetization direction by applying a magnetic field in the perpendicular direction to the magnetic shield.