C-Containing FePt Sputtering Target for Stable Magnetic Film Deposition

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Solution Overview

Problem

The existing ferromagnetic material sputtering targets used in magnetic recording media face challenges with carbon aggregation, leading to abnormal discharge and particle generation during sputtering, which affects the quality of the magnetic recording layer.

Innovation Solution

A C-containing FePt-based sputtering target is developed with a specific dispersion of a flat or tabular C phase aligned in a specified direction, utilizing a ratio of X-ray diffraction peak intensities to ensure stable sputtering and reduce particle generation, and incorporating additives like B, Ru, Ag, Au, and Cu to enhance magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon is added to the ferromagnetic material sputtering target to form granular-type magnetic recording layer, then the magnetic properties and corrosion resistance are improved, but carbon aggregation occurs leading to abnormal discharge and particle generation during sputtering

Engineering Contradiction:

Improvemagnetic properties and corrosion resistanceVSAvoidcarbon aggregation, abnormal discharge, and particle generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-dispersing carbon particles uniformly in the sputtering target before the sputtering process. The target is designed with carbon particles already distributed in a controlled manner throughout the ferromagnetic material matrix, preventing carbon aggregation during sputtering. This pre-dispersion approach eliminates the need for post-processing and ensures stable sputtering without abnormal discharge or particle generation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If carbon content is increased to enhance magnetic properties, then the magnetic recording layer performance is improved, but the target becomes difficult to sinter and causes abnormal discharge during sputtering

Engineering Contradiction:

Improvemagnetic recording layer performanceVSAvoidtarget sintering difficulty and discharge stability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by optimizing the carbon content within a specific range (0.1-5 wt%) and controlling the particle size distribution (0.1-10 μm). By adjusting these parameters, the target achieves both high magnetic recording layer performance and ease of manufacturing. The controlled carbon content prevents excessive sintering difficulty while maintaining enhanced magnetic properties, and the optimized particle size ensures uniform dispersion without causing abnormal discharge.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional sputtering methods are used with carbon-containing targets, then production efficiency is maintained, but particle generation affects the quality of magnetic recording layer

Engineering Contradiction:

Improveproduction efficiencyVSAvoidmagnetic recording layer quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of carbon into a beneficial one by utilizing carbon particles as intentional additives rather than impurities. The carbon particles are deliberately introduced and uniformly dispersed in the sputtering target to form a granular structure in the magnetic recording layer. This transforms carbon from a source of abnormal discharge and particle generation into an element that enhances magnetic properties and corrosion resistance, while maintaining production efficiency through conventional sputtering methods.

Inventive Principle:

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

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 solution enables stable sputtering and reduces particle generation, allowing for efficient deposition of a granular-type magnetic recording layer with improved magnetic properties, effectively addressing the issues of carbon aggregation and abnormal discharge.

Implementation Method 1

a magnetic thin film of a magnetic recording medium such as a hard disk is often produced by sputtering a ferromagnetic material sputtering target

Methodology Applied

Scientific EffectSputtering: Sputtering

Implementation Method 2

a ratio (X/Y) of an X-ray diffraction peak intensity of a graphite (002) plane in a cross section horizontal to a sputtering surface (X) relative to an X-ray diffraction peak intensity of a graphite (002) plane in a plane perpendicular to a sputtering surface (Y)

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS10325762B2Sputtering target for forming magnetic recording film and process for producing same

Publication Date: 2019.06.18 JX NIPPON MINING & METALS CORP

AI summary

A C-containing FePt-based sputtering target for forming a magnetic recording film, wherein a ratio of an X-ray diffraction peak intensity of a graphite (002) plane in a cross section perpendicular to a sputtering surface relative to an X-ray diffraction peak intensity of a graphite (002) plane in a plane horizontal to a sputtering surface is 2 or more. A magnetic recording layer is configured from a magnetic phase such as an Fe—Pt alloy and a nonmagnetic phase that separates the magnetic phase, and the sputtering target is a ferromagnetic material sputtering target in which carbon is used as a nonmagnetic phase material. When sputtered, the ferromagnetic material sputtering target is effective in preventing the generation of particles caused by an abnormal discharge originating from carbon, which is prone to aggregate.