HAMR Media Conductive Underlayer for DC Sputtering

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Solution Overview

Problem

Magnetic recording media for heat-assisted magnetic recording (HAMR) face challenges with the use of radio-frequency (RF) sputtering, which is energy-intensive, results in lower production yields, and is susceptible to particle contamination and corrosion due to the use of MgO underlayers, which are electrical insulators.

Innovation Solution

A magnetic recording medium is fabricated without an RF-sputtered MgO underlayer, using a substrate with a heat sink layer and an underlayer containing an electrically conductive material, allowing for direct current (DC) sputtering of FePt—Ag—X magnetic recording layers, where X is an oxide, thereby improving electrical conductivity and reducing corrosion risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RF sputtering is used to fabricate HAMR media with MgO underlayers, then magnetic recording performance can be achieved, but production yield is reduced and particle contamination occurs

Engineering Contradiction:

Improvemagnetic recording performanceVSAvoidproduction yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent removes the MgO underlayer from the HAMR media structure. This extraction eliminates the need for RF sputtering and its associated problems (particle contamination, corrosion, low production yield) while maintaining magnetic recording performance through alternative underlayer materials that are compatible with DC sputtering

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes RF sputtering with DC sputtering for the deposition process. This replacement eliminates the energy-intensive RF process and its associated drawbacks (particle generation, corrosion susceptibility) while achieving the same film deposition function through a simpler, more productive DC-based method

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If RF sputtering is used to deposit MgO underlayers, then underlayer formation is achieved, but energy consumption increases

Engineering Contradiction:

Improveunderlayer formationVSAvoidenergy consumption

Core Design Contradiction:

Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent replaces the energy-intensive RF sputtering system with a DC sputtering system for underlayer deposition. This substitution maintains the ease of manufacturing underlayers while dramatically reducing energy consumption by eliminating the RF power requirements and associated heating effects

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Temperature

If MgO underlayers are used in HAMR media, then thermal management is improved, but corrosion susceptibility increases

Engineering Contradiction:

Improvethermal managementVSAvoidcorrosion resistance

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent extracts/removes the MgO underlayer from the media structure. This elimination removes the corrosion susceptibility inherent to MgO while maintaining thermal management functionality through alternative underlayer materials and the heat sink layer that are inherently more corrosion-resistant

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs composite material strategies by combining alternative underlayer materials (such as Ru, Rh, or their alloys) with the heat sink layer to achieve both thermal management and corrosion resistance functions that MgO alone could not provide

Inventive Principle:

Principle #40Composite materials

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 approach enables higher areal density and improved magnetic performance with reduced dispersion and corrosion, achieving higher FePt intensity and signal-to-noise ratio compared to HAMR media with RF-sputtered MgO underlayers.

Implementation Method 1

heat sink layer on the substrate

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The underlayer includes an amount of an electrically conductive material between about 20 mole percent (mol %) and about 100 mol %

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

one or more layers of a HAMR medium can be fabricated using radio-frequency (RF) sputtering

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS20240096368A1Media structure configured for heat-assisted magnetic recording and improved media fabrication

Publication Date: 2024.03.21 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium. A magnetic recording medium includes a substrate, a heat sink layer on the substrate, and an underlayer on the heat sink layer. The underlayer includes an amount of an electrically conductive material between about 20 mole percent (mol %) and about 100 mol %. The magnetic recording medium further includes the plurality of magnetic recording layers on the underlayer. The plurality of magnetic recording layers includes a first magnetic recording layer that comprises FePt—Ag—X, wherein X is an oxide.