Fe-Pt Sputtering Target Oxide Adhesion
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Solution Overview
Problem
In the production of magnetic recording media, existing ferromagnetic material sputtering targets face issues with inadvertent release of metal oxides during sputtering, leading to particle generation due to abnormal electrical discharge at voids, and inadequate adherence between metal oxides and matrix alloys, which affects the density and quality of the magnetic recording layer.
Innovation Solution
A ferromagnetic material sputtering target is developed with a composition of Fe—Pt alloy and a metal oxide, where Pt is present in 5-60 mol%, the metal oxide has good wettability with a Calculated Wettability Index (CWI) of 25 J/molK or less, and is dispersed in a volume ratio of 15-70% with grain sizes between 0.1-50 μm, using oxides like Zr, Mg, Ti, Al, B, Ta, Nb, Zn, Si, Cr, Mn, and Ga, and optionally containing elements like B, C, Ru, Ag, Au, and Cu to enhance density and reduce particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ferromagnetic material sputtering target containing metal oxide is used, then the magnetic recording layer can be formed with non-magnetic phase, but inadvertent release of metal oxide and particle generation occur due to poor adherence and voids
Solution Approach 1:
The patent creates a composite material structure where metal oxide particles are embedded in a matrix alloy. The specific composition ratio (metal oxide 10-50 wt%, matrix alloy 50-90 wt%) and the use of Fe-Pt-based matrix with specific crystal structure form a composite that prevents particle release while maintaining sputtering functionality
Solution Approach 2:
The patent changes physical parameters including the crystal structure of the matrix alloy (controlling orientation to <001> direction), the composition ratios of metal oxide and matrix alloy, and the grain size distribution. These parameter changes optimize the adherence between metal oxide and matrix, preventing particle generation during sputtering
2Stability of the object's composition
If metal oxide is added to enhance non-magnetic phase, then magnetic grain isolation is improved, but adherence between metal oxide and matrix alloy deteriorates
Solution Approach 1:
The patent optimizes the composition parameters by controlling the weight ratio of metal oxide to matrix alloy within 10-50 wt%, and adjusts the chemical composition of the matrix alloy (Fe-Pt system with specific element ratios) to achieve optimal adherence while maintaining magnetic grain isolation functionality
3Reliability
If sputtering target density is increased to reduce voids, then abnormal electrical discharge is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent achieves high density (90-99% theoretical density) by controlling sintering parameters including temperature (1000-1500°C), pressure (1-100 MPa), and atmosphere conditions. The Fe-Pt matrix alloy's specific crystal structure and composition facilitate densification while reducing void formation
Solution Approach 2:
The composite structure of metal oxide particles dispersed in Fe-Pt matrix alloy creates a dense configuration where the matrix fills void spaces, achieving high overall density without requiring excessively complex densification processes
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 target effectively suppresses particle generation and enhances adherence between the metal oxide and matrix alloy, achieving a high-density sputtering target suitable for forming magnetic recording layers with improved magnetic properties, particularly for granular magnetic recording media.
Implementation Method 1
the magnetic thin film of a magnetic recording medium such as a hard disk is produced by sputtering a ferromagnetic material sputtering target
Implementation Method 2
the adherence between a metal oxide and a matrix alloy is required to be enhanced
Data Source
AI summary
An Fe—Pt-based ferromagnetic material sputtering target comprising a metal and a metal oxide, wherein the metal has a composition in which Pt is contained in an amount of 5 mol % or more and 60 mol % or less and the remainder is Fe. An object of the present invention is to provide a ferromagnetic material sputtering target, which enables to form a magnetic recording layer composed of a magnetic phase such as an Fe—Pt alloy, and a non-magnetic phase to isolate the magnetic phase, and in which a metal oxide is used as one of the materials for the non-magnetic phase. Provided is a ferromagnetic material sputtering target wherein an inadvertent release of the metal oxide during sputtering and particle generation due to abnormal electrical discharge starting at a void inherently included in the target are suppressed, the adherence between the metal oxide and the matrix alloy is enhanced, and its density is increased.