Magnetic Sputtering Target Oxide Grain Control
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Solution Overview
Problem
Magnetic material sputtering targets with non-magnetic oxide grains, such as SiO2, Cr2O3, or TiO2, cause abnormal discharge and particle generation during sputtering due to their insulative nature, which is problematic for high-density magnetic recording media.
Innovation Solution
A magnetic material sputtering target with oxide grains having an average diameter of 1.5 μm or less, where 60% or more of the grains are spherical or sphere-like with a diameter difference of 0.4 μm or less, dispersed in a metal phase containing Co or Fe, and additional elements like Pt, Cr, and other oxides, achieving a relative density of 97% or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If non-magnetic oxide grains (SiO2, Cr2O3, TiO2) are added to the magnetic material sputtering target, then the target structure is formed for perpendicular magnetic recording, but abnormal discharge and particle generation occur during sputtering due to the insulative nature of the oxide
Solution Approach 1:
The invention changes the physical and chemical parameters of the oxide grains, specifically controlling the grain size to 10 μm or less and adjusting the composition ratio of oxide to metal powder within 1-50 wt%. These parameter changes reduce the insulative effect while maintaining the structural requirements for perpendicular magnetic recording, thereby suppressing abnormal discharge and particle generation during sputtering
Solution Approach 2:
The invention creates a composite material system combining magnetic metal powder (Co, Co alloy, or Fe-based) with non-magnetic oxide grains. The composite structure maintains the necessary target composition for perpendicular magnetic recording while optimizing the distribution and size of oxide grains to minimize their harmful insulative effects during the sputtering process
2Ease of operation
If oxide grains are dispersed in the metal phase, then the target can be used for sputtering, but the insulative oxide causes abnormal discharge
Solution Approach 1:
By controlling the oxide grain size to 10 μm or less and adjusting the oxide content within 1-50 wt% of the total composition, the invention reduces the insulative barrier effect of the oxide grains. This maintains reliable plasma discharge stability while preserving the sputtering capability needed for film formation
3Manufacturing precision
If conventional powder metallurgy method is used to disperse inorganic grains uniformly, then the target structure is achieved, but abnormal discharge occurs due to oxide insulative properties
Solution Approach 1:
The invention optimizes the oxide grain size parameter to 10 μm or less and controls the oxide to metal weight ratio within 1-50 wt%. These parameter changes maintain uniform dispersion of inorganic grains for proper target structure while reducing the harmful insulative effects that cause abnormal discharge during sputtering
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 prevents abnormal discharge and significantly reduces particle generation during sputtering, ensuring stable discharge and improved yield, making it suitable for high-density magnetic recording media.
Implementation Method 1
a high density of plasma can be concentrated near the front surface of a target by disposing a magnet on the back face of the target and leaking a magnetic flux to the front surface of the target
Implementation Method 2
Many of magnetic thin films of magnetic recording media such as hard disks are produced by sputtering a magnetic material sputtering target
Data Source
AI summary
A magnetic material sputtering target characterized in that, in a plane for observing the oxide in the target, oxide grains in the target have an average diameter of 1.5 μm or less, and that 60% or more of the oxide grains in the observing plane of the target have a difference between a maximum diameter and a minimum diameter of 0.4 μm or less, where the maximum diameter is a maximum distance between arbitrary two points on the periphery of an oxide grain, and the minimum diameter is a minimum distance between two parallel lines across the oxide grain. A non-magnetic grain dispersion-type magnetic material sputtering target that can inhibit abnormal discharge due to an oxide causing occurrence of particles during sputtering is obtained.