Multi-Layer HAMR Media Underlayer for Corrosion and Heat Control

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Solution Overview

Problem

Existing heat-assisted magnetic recording (HAMR) media face issues with corrosion and lower thermal barrier resistance due to the use of magnesium oxide (MgO) layers, leading to head-disk interface problems and increased power requirements for laser heating.

Innovation Solution

A seed-thermal barrier structure comprising a first MTO layer, a TiN layer, a middle thermal barrier layer, and a second MTO layer, which includes materials like RuAl, providing additional thermal resistance and reducing corrosion, while maintaining optical coupling and magnetic grain ordering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a MgO layer is used in HAMR media, then thermal barrier resistance is reduced, but corrosion resistance deteriorates

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidthermal barrier resistance

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent replaces the single MgO layer with a composite underlayer structure consisting of multiple layers including MTO (magnesium tungstate oxide), RuAl (ruthenium aluminum alloy), and TiN (titanium nitride). This composite structure combines materials with complementary properties: MTO provides chemical stability and corrosion resistance, RuAl provides high thermal barrier resistance, and TiN provides adhesion and corrosion protection, thereby simultaneously improving both corrosion resistance and thermal barrier resistance

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent divides the single MgO layer into multiple segmented layers with distinct functions. The underlayer structure is segmented into: (1) MTO layers for chemical stability and corrosion resistance, (2) RuAl layer for thermal barrier resistance, and (3) TiN layer for adhesion and corrosion protection. Each segment performs its specific function, collectively resolving the contradiction between corrosion resistance and thermal barrier resistance

Inventive Principle:

Principle #1Segmentation

2Power

If laser power is increased for heating, then recording capability is improved, but head lifetime deteriorates

Engineering Contradiction:

Improvelaser powerVSAvoidhead lifetime

Core Design Contradiction:

PowerVSDuration of action of moving object

Solution Approach 1:

The patent converts the harmful effect of high laser power (which reduces head lifetime) into a benefit by designing an underlayer structure that optimizes heat confinement. The RuAl layer with high thermal barrier resistance prevents heat from spreading to the heat sink, allowing efficient heating of the recording layer at lower laser powers. This transforms the problem of high power requirements into an advantage where lower powers achieve the same effect, extending head lifetime

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If MgO layer is used, then manufacturing simplicity is maintained, but thermal barrier resistance deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidthermal barrier resistance

Core Design Contradiction:

Ease of manufactureVSTemperature

Solution Approach 1:

The patent changes the material parameters of the underlayer from single MgO to a multi-layer composite with controlled thicknesses and compositions. By optimizing the thickness of each layer (MTO, RuAl, TiN) and their material properties, the structure achieves superior thermal barrier resistance while remaining compatible with existing sputter deposition manufacturing processes, thus maintaining ease of manufacture despite the increased structural complexity

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

The new structure enhances thermal resistance, reduces laser power requirements, and improves signal-to-noise ratio, thereby increasing HAMR head lifetime and system reliability.

Implementation Method 1

a heat sink layer on the substrate

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

an underlayer structure on the heat sink layer. The underlayer structure includes a first layer comprising MgOTiO (MTO) on the heat sink layer, a second layer comprising TiN on the first layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS12412598B2Media underlayer structure for heat-assisted magnetic recording and media fabrication methods therefor

Publication Date: 2025.09.09 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

Various apparatuses, systems, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that includes a HAMR medium with a seed-thermal barrier structure. The seed-thermal barrier structure is positioned between a heat sink layer and a magnetic recording layer. In some examples, the seed-thermal barrier structure has a first layer including MgOTiO (MTO), a second layer including TiN on the first layer, a third layer on the second layer, and a fourth layer including MTO on the third layer. The third layer, in some examples, includes at least one of: RuAl, Pt, PtZr, PtTa, Rh, FePt, CrMo, or Cr.