Ferromagnetic Sputtering Target Spherical Phase Design
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Solution Overview
Problem
Ferromagnetic material sputtering targets used in magnetron sputtering devices experience unstable electrical discharge due to high leakage magnetic flux, which can be mitigated by adjusting the target structure but requires a solution that maintains magnetic recording medium characteristics.
Innovation Solution
A ferromagnetic material sputtering target with a metallic substrate and a spherical phase containing 90 wt% or more Co, where the difference between the longest and shortest diameter is 0 to 50%, and additional elements like Ti, V, Mn, Zr, Nb, Ru, Mo, Ta, and W, with a relative density of 98% or more, to enhance leakage magnetic flux and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a ferromagnetic material sputtering target is used in a magnetron sputtering device, then the productivity of magnetic thin film deposition is improved, but the leakage magnetic flux increases causing unstable electrical discharge
Solution Approach 1:
The patent applies local quality by creating a non-uniform microstructure within the sputtering target, specifically forming a dual-phase structure where a ferromagnetic alloy phase (containing Co, Cr, Pt) coexists with a nonmagnetic inorganic phase (such as SiO2 or Al2O3). This local differentiation of magnetic properties within the target material allows the ferromagnetic regions to maintain high leakage magnetic flux for productivity while the nonmagnetic regions provide pathways for flux leakage, thereby stabilizing the electrical discharge. The nonmagnetic inorganic particles are dispersed throughout the ferromagnetic alloy matrix, creating localized zones with different magnetic characteristics that collectively resolve the contradiction between productivity and discharge stability.
2Reliability
If the target structure is adjusted to reduce leakage magnetic flux, then stable electrical discharge is achieved, but the magnetic recording medium characteristics deteriorate
Solution Approach 1:
The patent employs composite materials by combining ferromagnetic alloy particles (Co-Cr-Pt base) with nonmagnetic inorganic particles (SiO2, Al2O3, or other oxides) to create a heterogeneous target structure. This composite approach allows the ferromagnetic phase to maintain the necessary magnetic properties for recording medium performance while the nonmagnetic phase provides flux leakage pathways for stable discharge. The synergistic combination of materials with contrasting magnetic properties enables simultaneous achievement of discharge stability and magnetic characteristics preservation. The nonmagnetic inorganic component acts as a flux shunt without compromising the ferromagnetic recording layer quality.
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 adjusted target structure achieves stable electrical discharge, prolongs target life, and reduces replacement frequency, enabling low-cost production of magnetic thin films with improved magnetic recording medium performance.
Implementation Method 1
a spherical phase (B) containing 90 wt % or more of Co in which the difference between the longest diameter and the shortest diameter is 0 to 50%
Implementation Method 2
the sputtering method employs a fundamental principle where inert gas is ionized, plasma composed of electrons and positive ions is formed, and the positive ions in this plasma collide with the target (negative electrode) surface so as to discharge the atoms configuring the target
Implementation Method 3
A magnetic thin film of a magnetic recording medium such as a hard disk is often produced by sputtering a ferromagnetic material sputtering target
Data Source
AI summary
A ferromagnetic material sputtering target made of metal having a composition containing 20 mol % or less of Cr, and Co as the remainder thereof, wherein the structure of the target includes a metallic substrate (A), and, in the metallic substrate (A), a spherical phase (B) containing 90 wt % or more of Co in which the difference between the longest diameter and the shortest diameter is 0 to 50%. Provided is a ferromagnetic material sputtering target capable of improving the leakage magnetic flux to obtain a stable electrical discharge with a magnetron sputtering device.