Magnetoresistive Element Side Surface Protection

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Solution Overview

Problem

Existing methods for manufacturing magnetoresistive elements, such as those used in MRAM, face challenges with short-circuits due to conductive deposits adhering to side surfaces during ion milling, requiring additional chemical treatments and complex masking processes, which can lower manufacturing yield and reliability.

Innovation Solution

A magnetoresistive element configuration with a lower magnetic layer, a barrier layer, and an upper magnetic layer, where the barrier layer's first surface contacts the lower magnetic layer's upper surface, and the upper magnetic layer's second surface contacts the barrier layer's upper surface, both surfaces being larger than the lower magnetic layer's surface, prevents short-circuits by ensuring adequate separation and using an interlayer insulating layer to prevent electrical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ion milling is used to form separation grooves, then manufacturing speed is improved, but conductive deposits adhere to side surfaces causing short-circuits

Engineering Contradiction:

Improvemanufacturing speedVSAvoidshort-circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A protective film is formed on the side surfaces of the magnetic tunnel junction part before ion milling. This preliminary protective coating prevents conductive deposits from adhering to the side surfaces during the ion milling process, thereby avoiding short-circuits while maintaining the manufacturing speed benefits of ion milling.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective film acts as an intermediary layer between the ion milling process and the magnetic tunnel junction part. This intermediate layer prevents direct contact between the ion beam and the side surfaces, blocking the harmful deposition of conductive materials while allowing the separation groove to be formed effectively.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If chemical treatment is used to remove deposits, then short-circuit prevention is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveshort-circuit preventionVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using chemical treatment after ion milling to remove deposits, a protective film is applied beforehand. This preliminary protective measure prevents deposit formation in the first place, eliminating the need for subsequent chemical cleaning steps and simplifying the overall manufacturing process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The harmful chemical treatment step is extracted and removed from the manufacturing process. By using a protective film to prevent deposit adhesion, the complex chemical cleaning operation becomes unnecessary, reducing process complexity while maintaining reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If additional masking steps are used to protect surfaces, then short-circuit prevention is improved, but manufacturing time increases

Engineering Contradiction:

Improveshort-circuit preventionVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The protective film formation is merged with the existing manufacturing process flow, combining the protection function with the deposition process. This integration allows side surface protection without requiring separate masking and unmasking steps, thereby preventing short-circuits without increasing manufacturing time.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The complex multi-step masking process is extracted and replaced by a simpler protective film deposition approach. This removal of unnecessary masking steps reduces manufacturing time while maintaining effective side surface protection against conductive deposits.

Inventive Principle:

Principle #2Taking out (Extraction)

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 enhances the reliability and yield of magnetoresistive elements by preventing short-circuits and allowing for more straightforward manufacturing processes, improving the overall performance and consistency of MRAM production.

Implementation Method 1

the barrier layer and the upper magnetic layer are etched

Methodology Applied

Scientific EffectIon milling: Ion Beam

Implementation Method 2

The magnetoresistive element stores data as a magnetization direction of the free layer

Methodology Applied

Scientific EffectMagnetization: Magnetism

Data Source

PatentUS8796793B2Magnetoresistive element, magnetic random access memory and method of manufacturing the same

Publication Date: 2014.08.05 RENESAS ELECTRONICS CORP

AI summary

A magnetoresistive element includes: a lower magnetic layer; a barrier layer; and an upper magnetic layer. The barrier layer is provided on the lower magnetic layer. The upper magnetic layer is provided on the barrier layer. One of magnetization directions of the lower magnetic layer and the upper magnetic layer is fixed. The barrier layer has a first surface which includes a surface contacted with an upper surface of the lower magnetic layer. The upper magnetic layer has a second surface which includes a surface contacted with an upper surface of the barrier layer. Each of the first surface and the second surface is larger than the upper surface of the lower magnetic layer in area.